CA2142293A1 - Method and apparatus for incubating and hatching eggs - Google Patents

Abstract

2142293 9404024 PCTABS00030 An egg tray is provided which holds the eggs at an angle of approximately 35· relative to the horizontal floor of the tray with the large or air-cell end of the egg being elevated. Air vents (58, 60) in the tray sides permit fresh air to flow directly over the eggs during incubation. A hatchery facility includes racks for holding a plurality of such trays loaded with eggs. The loaded racks are rolled into an incubation and hatching chamber (80) through a first set of doors (106) which connect the chamber to a first hallway in which fresh air is circulated. After incubating and hatching, the racks and air control unit in each chamber are removed through a second set of doors (108) into a second hallway in which air from the chambers is vented during incubation and hatching. The air pressure in the first hallway is greater than that in the second hallway thereby minimizing the risk of contamination.

Description

wo 94/04024 2 1 4 2 2 9 3 PCr/CA92/~0354 MEq~OD AND APP~ATUS FOR INCU~TING AND ~A~CHING EGGS

BACKGRO.UND OF q~HE IN~IENTION
1. ~-IL~
The pr~sent in~tion-~lates to me~hods and~apparatus ~or incubating and hatch-~g eg~s. and mor~ particularly to such methods and apparat~ in wh~ch trays holding a plurality of egg~ are receiYed in a controlled environment for promoting incubation and hatching

2. Descripti~n of ~he Related Art Trays for receiving eggs during the ~ ncubation process ha~e been in use for many year~. GQnerally speaking, a tray i8 loaded with freshly-laid eggs and is thereafter rece~ved in a rack or the l~ke along with a number of other loaded egg trays.
The rack is positioned in a chamber in wh~ch the en~ironment, especially temperature and humidity, i~ controlled to maximize the number of chicks hatched from the eggs. Most, but not all, ~ncubation and hatching mathods involve incu~ating in a first tray which is designed to optimize incubation condition~. Just prior to hatching, the ~ggs are transferred to a 6econd hatching tray which i 8 designed to accommodate the hatched chicks. Prior art methods include placing the egg on a ~ubstantially planar sur~ace in an Qgg tray.
During incubation, the trays are tilted about a horizontal axis to simulate the ~am~ egg movement caused by a hen, through the use o~ her beak and feet, in a nest. Such movement is important during-the incubation process because the chick embryo floats for ~he f~rst 14 days of incubat~on and will stick to the upper ~urface o~ th~ egg and die if the egg i8 not rotated. On or about the 14th day incubation, the chick orients itself with its head in the end of the egg which is tilted upwardly, which should be the large end containing the air ~ell.
During ~atching, which occurs on or about the 21st day of incubation, the chick uses its beak to peck through the egg ~hell along a circle near the air-cell end of the egg and substantially coaxial with the longitudinal axis of the egg.

SUBS~ITUTE SHEET
. . ., . ,. . . ... . ... . .. .. . . . .. ~ . .~ . ~ .. ... ... .. . . .. ..

wo g4/~24 2 1 ~ 2 ~ 9 3 PCT/C~XV~0354 The end of ~he egg is thus removed ~nd the chick can emerge ~rom the egg.
I~ the small end of the egg is t~lted up when the chick positions itself ~he chick may malpo~ition with it~ head in the small end of the egg. When ~he chic~ fir~t pip8 the shell and begins to breathe, i~ will drown. Even with the chick'~ head positioned in the air-cell end, if any part of the e~g ~hrough which the chick ~ust peck is against another object, such as the ~loor of the egg tray or an ~djacent ~gg, the ehick may not ~e able to peck through the ~hell and thus dies~
Sometimes the egg tray tilt~ng wh~ch must be undertaken during incubation causes the eggs to roll against one another or the egg tray in a manner which may pr~vent chick hatching as described above~ The small end of one egg may ride up onto an adjacent egg or a portion of the tray thereby tilting the longitudinal axi~ of th~ Qgg ~0 that the a~r-ce~l end is against the floor o~ the tray. If the small Qgg end ~s higher than the air-cell end, the problems described abo~e may develop.
Prior art egg trays and incubation and hatching methods thus su~fer *rom disadvantages which reduce the yield and quality of hatched chicks.
In addition to the foregoing described problemsl the yield o~ hatched chicks is also r~duced a8 a result of conta~ination 2~ in the incubation chamber. A typical hatchery includes a number of incubation chambers into which portable racks of loaded egg trays are placed for incubation and hatching.
In some methods, the incubation chamber holds eggs at widely varying stages ~f incubation. The racks supporting the egg trays are serially ~oved through the incubator with a rack at one snd having fresh Qggg and with eggs in a rack at the other end being ready to hatch. In such a method the doors to the incubator chamber are opened and closed a number of times during incubation. This permits contamination ~rom chick down and waste to spread from other parts of the hatchery into the chamber.
In other hatchery methods, an incubation chamber is loaded with racks containing fresh eggs and the incubation process is begun. Thus, the doors to the incubation chamber are not c1~ ~1 ITF ~HEET

~094/ ~ 24 PCT/CAg2/003~4 opened dur~g inaubation, unl~s it is a sy~tem in wh~ch the eggs are trans~erred ~rom incubator trays to hatching trays prior to hatching. Down.and waste contamination Gan, however, enter the cha~ber whsn the racks bearing the fresh eggs are first placed in the chamber.

SUMMARY OF TXE INVE~TION
In one aspect, ~he present invention co~pri~es a tray for incubating and hatching eggs whi~h includes a plurality o~
curved urfaces ~ormed on the tray bottom for holding an egg so tha~ the long~tudinal axi6 of the egg forms an acute angle relative to the tray bottom with the air-cell end of the ~gg being ~urther from thB tray bottom than the other end.
In another aspect o~ the invention, a facility for in~ubating and hatching Qggs i5 pro~ded which includes a ~ir~t plenum ~ ad with fresh air. An egg incubating and ~atching cha~ber receives an egg rack ~rom th~ first plenum. ~re~h air i8 com~unicated from the first pl~num to the ch~mber during egg incubation and hatching. The rack is mo~eable from the chamber into a second plenum after incubat~on and ~atching. During incubation ~nd hatching, chamber air i8 exhausted into the ~econd plenum.
. It ~8 a general obj~ct of the present invention to proYide a method and apparatus for i~cu~ating and hatching egqs wh~ch overcomes the above-enumerated di~advantages associated with prior ar~ methods and apparatus.
It is another object o~ the present invention to provid~
an improved tray in which e~s can be both incubated and hatched.
It is a more specific object of the present invention to provide such a tray which improv~s the yield and quality of hatched chioks.
It is yet another ob~ect o~ the present invention to provide ~uch a method and apparatus which reduces ~gg

3~ contamination during ~ncubatlon thereby increasing the yield and ~uality of hatched chicks.
The foregoing and other objects, features and advantages -of ~he invention will become more readily apparent from the SUBS~ITUTE SHEET

W094/~ PCT/~Ag2/003~

following detaila~esoription o~ a prefQrr~d embodiment which proceeds with reference to th~ drawinqs~
~-- t~r ... BR$~:~ESCRIPTION OF THE D~AWINGS
Fi~. 1 is a to~.plan ~uiew of a tray ~or in~ubating ~nd ha~ching eggs ons~ucted in accordance with the pre~ent invention. - . ' F~g. 2 is ~n enlarged ~ectional view taken along line 2-2 i~ Fig. 1.
Fig. 3 is an enlarged, partial plan view of the ~gg tray :
of Fig. 1 stacked on and nested with~n another such egg tray.
Fig. 4 is a view taken along line 4-4 in Fig~ 3.
Fig~ 5 i~ a partial, bottom plan view o~ the upper egg tray in Fig. 3.
F~g. 6 is a partially diagrammatic plan view of a hatchery facility conætructed in accordance with the pre~e~t invention.
Fig. ~ is an enlarged partial ~iew of the hat~hery facility o~ Fi~. 6.

DETAI~ED ~ESC.RI~TION OF THE PREFE~RED EMBOD ~
Turn~ng now to the drawing and considering Figs. 1 and 2, ind~cated gener~l`ly at 10 i~ a tray ~or incubating and hatching eggs. Tray 10 is constructed i~ accordance w~th the pre~snt invention. The tray includes a bottom 12 and side walls 14, ~; 25 16, 18, 20.
Botto~ 12 includes wh~t is refarred to herein as a horisontal egg support surface 22. The egg support surface is bounded by side walls 14-20 and includes fi~e rows and 12 columns of egg-holding recesses, like recesses 24, 26. The egg supporting recess@s are also referred herein as holding m~ans or curved surfaces. As aan perhap~ be best viewed ~n Fig. 4, surfaces 24, 26 are each asymmetrical in shape and are formed ~o as to hold an egg, lik~ egg 28 (shown in dot-d~sh l~n~s), with it~ narrow end tilted downwardly relative to surface 22 3~ and its big or air-cell ~nd t~lted upwardly as illustrated in Fig. 3.
A~ can be seen in ~igs. 2, 4 and 5, the underside of bottom 12 includes reinforcing webs, like webs 30, 32. The underside of each web is substantially co-planar with the ~6~TITIJTE SHEET ~

W094/~W~ 2112293 pCT/cA92/0o3s4 underside of all th~ o~h~r webs on bottom 12. Such structure provide~ a ~l~t lower surface for supporting tray 10 when the ~me i8 ~et on a flat ~urf~cQ.
Each of the sid~ walls include ~ downwardly-dir~cted S exterior shouldQr, like ~houlder~ 34, 36 on walls 18, 20, respectively. As can be se~n in ~ig. 2, the shoulders ~re const N cted to cooperate with rods 38, 40 on a 60nventional rack (not shown~ for ~upporting a plurality o~ egg trays like tray 10.
Each of the 8~ de walls ~urther includes an upwardly-directed interior shoulder, like shoulders 42, 43, 44 on side walls 18, 14, 20, respectively. Vertical upport webs, like webs 46, 48, 50, extend from ~urfac~ 22 a~ the lower end o each web to the plane of the upwardly-directed ~houlders, like shoulders 42, 43 at the upper end of each web. The upper end of each of the webs, li~e we~s 46, 48, thus comprises a portion of its a3socia~ed upwardly-directed shoulder, l~e shoulders 42, 43, respectively.
~ Associated with each support web i5 a guidi~g means or guide we~, like guide webs 52, 54 are associated with support webs 46, 48, respectively. Each o~ th8 guide webs includes an upper ~urface, l~ke upper ~ur~acQ 56 on web 52, which extends betw~en an uppor web position nd~acent the aid~ wall upon which the guide web is formed to a lower interior position. As will later become more fully app~rent, when the bottom o~ one tray like tray 10 is lowered into the top of another tray, also li~e tray 10, the guide webs serve to center the upper tray relat~ve to the lower tray 80 that the lowes surface of the upper tray side walls is guided to the upper surfa~e of the support webs on the lower tray. This confiyuration is illustrated in Fig.

4.
A plurallty of air vents, like vents 58, 60 are dlsposed in ~ach side wall and extend upwardly from shoulder 43 as shown. Each side wall includes a pair of such vents aligned 3~ with the recesses, like recesses 24, 26, in each of the rows and columns. It can thus be seen that air is free to circulate directly abo~e eggs received in the recesses in a first direction between walIs 14, 16 and at right anqles thereto, between walls 18, 20.
Sl~BS~lTUTE S~lEET

.

wo~/~ 21 4 2 2 9 3 PCT/CA92/003~

Turning n~w to Fig~. 6 ~nd 7, ¢on~ideration will b~ gi~n to structure and operation of a hatchery ~a~ility, indicated generally at 62 in Figs..6, in which trays like tray 10 may b~
utilized to hold e~qs during hatching and incubation. ~he

5 facility i5 bounded by an exterior wall 64. An egg unloading dock 66 facilitate~ unloading of egg~ from vehicle~, preferably carried in trays like tr~y 10 and stacked as illustrated in Fig. 4. A chick ~oading do~k 68 permits loading of hatching ch~cks ~rom fa~ility 64 onto vehicles for transport to farmc where the chicks are rai~ed.
The hatchery incl~des hallways 70, 72, 74, 76 which compriæe w~at is referred to herein as a first plenum.
Hallways 70-76 are provided wit~ a flow of fresh air $rom a conventional air-treatment system (not shown). The hallways lS are isolated ~rom thQ atmosphQr~ out~id~ the facility via conventional ~ir lock~ ( al80 not ~ho~n) inco~porated into hatchery 64. A plurality of ~gg incubating and hatching c~ambers, three o~ which ara c~amber~ 78, 80, 82 are provided along hallways 72, 74, 76. Figure 7 comprises an enlarged and more detailed, but ~till ~chemat$c, view of chamber 80 and portions of 78, 82.
Each of the egg chamber~, lik~ chamber 80, is constructed ~ubst~ntially in ac~ordanc~ with the incubation chamber illustrated in U.S. Patent No. 5,025,619, i~sued June 25, lg91 for: Method and Apparatus for Incubating and ~atching Eggs, w~i~h patQnt is insorporated herein by reference. Generally speaking, and with reference to Fig. 7, chamber 80 includes a pair of egg-tray racks 84, 86 illustrated in dashed lines, which are of conventional construction. Racks 84, 86 are mounted on wheels (not shown) are rollable to different locations within hatchery 64. Each of racks 84, 86 support a plurality of egg trays, l~ke tray 10, via ~upp~rting rods, like rods 38, 40 in Fig. 2, on the racks.
Chamber 80 further includes an air control unit 88 constructed in accordance with U.S. Patent No. 5,025,619. A
hose 90 is mounted on one end of the air control unit and is releasably connected it the other end to a wall 92 which makes up one side of hallway 74. A port (not visible) formed in wall SUBS~TUTE SHEET

W094/~24 2 1 4 2 2 9 3 pCr/CAg2/Q0354 92 permits CGm~ C tion of air in hallway 74 to control unit 88 via hose 9o.
A cold w,-it~ upply hosa Cnot shown) and a cold water return hose are ~ connected to the air control unit as are hot water suppl~ ~nd return hos~s ~or regulating the temperature in cham~.ar ~O as descri~ed in U.~. Patent No.
5,025,619. The wa er hose~ are releasably connected to water supply and return lines in each chamber as described in more detail hereinafter. To ~i~plify the drawing herein, the water lo ho~es re not illuctrated.
F~ns, as described in U.S. Patent No. ~,025,619, mounted on air ~ntrol unit 88 circulate air in chamber 80.
k v~nt pipe is formed on a wall 96 which make up one side of a hal.~ay 98 ~in Fig. 6.). Hallway 98 along with hallways 100, ~02, and 104 comprise what is re~erred to herein as a second ~lenum.
Vent pipe 94 is constructed and operates in the same manner as ~he vent pipe in U.S. Patent No. 5,025,619 which, however, is ~hown~on the c~ ng o~ the incubation and hatc~ing chamber.
Chamber 80 further includes a first ~et of doors 106 and a ~econd set of doors 108. Door# 106, 108 are also referred to here~n as sealable opening~. As will be hereinafter explained, the doors perm~t movement of rack~ 84, 86 and air control unit 88 from hallway 74 into chamber 80 whilQ doors 108 permit movement of th~ racks and air control unit from the chamber into hallway 98.
Consider~ng again Fig. 6, a con~entional heat exchanger 110 is connected to piping 112, ~hown only diagrammatically, for providing a cold water supply line to each of th~ chambers, like chamber 80. Similarly, a cold water return line runs from each chamber back to exchsnger 110 wher~ heat is removQd therefrom and released into hatchesy 64 thereby regulating the temperature in the chambers, as described in the '943 application and heating the remainder of hatchery 64.
Hatchery 64 further includes a washroom 114, which is connected to hallway 104 via door 116. A clean-room 118 is connected to washroom 114 by a door 120 and to hallway 76 by a door 122. A chick-room 124 receives hatched chicks prior to SUBSTITUTE SHIEET

~ 2142293 WOg4/~2~ PC~/CAg2/0~354 loading the ~a~n dock ~8. O~her roo~s ~n hatchery 64 are provided ~or..~as~p.~nd mechanical fac~l~ti~s a~ well as o~fi¢e space.
. Consideration iB now given to th~ manner in which trays, lik~ tray 10, are used in connection with hatchQry 64.
Initially, fresh fertilized eggs are laid in a plurality of trayC, like tray ~0 in Fig~ 4, in the tray upon which it i8 stacked. As can be seen in Fig. 4, the longitudinal axi~ o~
each of the eggs, like e~g 28, is at an angle of ~pproximately 35- with respect to ~urfa~e 22 and the large or air-cell end of the sgg 28 i8 tilted upwardly. Preferably the angle i8 approximately 35~. An angle o~ 20-; however is sufficient to obtain the beneficial results of the present invention.
once a nu~ber of trays are so loaded and stacked, the same are transported to facility 64 whereupon they are unloaded at doc~ 66~ At the d~c~ the same are loaded onto egg ra~ks, like racks 84, 86. When received upon the rods, like rods 38, 40 (in Fig. 2), which support the egg trays in th~ rac~s, each rack is separated from the rack therebelow by a space sufficient for a chick to stand upright on surface 22. Such spacing provides a gap b~tween the uppermost port~on of one tray and lowermost portion o~ the tray therQabov~ thereby al~o permitting fresh air to circulate imme~iately over and around the h~ad of a ch~ck standing on surface 22. ~s will be recalled, the vents, lika vents 58, 60, permit circulation of air directly over the eggs prior to hatching.
Wh~n the racks are 80 loaded, they are rolled substantially a~ong the dotted line Fig. 6 and ~nto chamber 80 through open door~ 10~ whereupon the doors are closad.
30 Thereafter, the twenty-one day ~ncubation proc~ss starts during which air control unit 88 regulates tQmperature and humidity as desori~ed in the '943 application. During such incubation, it is necessary to tilt the egg trays in order to prevent the embryo in each egg from sticking to the upper 3S surface of the egg. Racks 84, 86, include a conventional mechanism for tilting the egg trays to achieve this end. The angle of tilt is sufficient to prevent the embryo from sticking Sut is not so gr~at as to cause eggs to roll out-of their recesses, like recess 24. The position of each egg thus SUBSTITUTE SHEET

WO940~J424 2 1 ~ 2 2 9 3 p~f/C~2/003s4 r~mains completely un~hanged with the 2gg~ remaining separate from one another ~fter tray tilting.
After incu~a~L~n, during which time th~ environmental ~ondit~ons in ~ha~bar 80 are regulated as set forth in the ~943 application and thc~t~ays are tilted by the racks in accordance with a known proce~ur~ th~ chicks hatch. The manner in which a chick p$ps throu~the shell of ~n egg ~s illustrated by the broken shell of e;~ b~n Fig. 4. As can be seen, the chick pips through the Ehe~ in a substantially circular pattern 19 which i~ substantially coaxial w~th the ~is o~ the egg.
During the incubation, fresh air is pro~ded to chamber 80 from hallway 76 via hose 90. The air is humidified snd heated or cooled by air control unit 88 as set forth in the '943 application. Air is vented from chamber 80 ~ia vent pipe 94f also as ~et forth in U.S. Patent No. 5,025,619.
It should be noted that the a~r pressure in hallway 76, and the other areas which mak~ up the first plenu~, is maintained ~t a higher pressure than tha pressure in hallway 102, ~nd t~e related areas wh~ch make up the second plenum.
~20 I~ any opening bQtween the plenums occurs, flow therefor~ is from the first or fresh air plenum to the second or exhaust plenum. This fea~ura is important becausa a~r is vent~d, via a~r vent 94, into hallway 102. In addition, after hatching, the chic~s are rQmoved into hallway 102 via doorR ~0~. ~allway 102 and the related areas making up the second p~enum are thus contaminated by down, wasta and any other bacteria dQ~eloped in the trays during incubat~on. ~f there ~hould b~ an opening between the first or fresh air plenum and second plenums, flow is thus always from ~he first plenum to the second plenum thereby preventing contamination of the fresh air.
Vpon removal from chamber 80 the chicks are taken to chick room 124 where they reside temporar~ly until loaded onto a vehicle fr~m dock 68 for transport from the hatchery. The dotted line beginning on dock 66 and ending dock 68 thuæ
illustrates the path of eggs and, after incubation and hatching in chamber 80, the chicks through the hatchery facility.
After the chicks are removed from chamber 80, the water hoses (not shown) are disconnected from air control unit 88 as is hose 90 and unit 88 is rolled out of chamber 80 via doors ~IIRS~ITUTE SHEET

wo 94/~ ~24 2 1 4 2 2 9 3 PCT/CA92/00354 108 and into washroom 114 for a thorough cleaning. ~he clean unit i~ thereafter rolled via door 120 into clean ro~m 118 and from there, when needed, to on~ of th~ incubation chambers, like chamber 80.
Also, after the egg tray racks and air control unit are removed from chamber 80, cleaning egUipmQnt is brought into hallway 98 and the interior o~ th~ chamber is thoroughly cleaned and ~crubbed by entering the same through doors 108.
During this time doors 106 remain closed thus isolating thé
chamber from the fresh air plenum. After such cl~aning, doors 108 are closed and doors 106 opened to receive a clean air control unit and two additional egg trays.
It should be noted that throughout incubation and hatchinq both doors 106, 108 remain ciosed thereby r~ducing the r~k of contamination in the egg chamber. Since it not necessary to transfer the eggs ~rom an incubation tray to a hatching tray the risk of contamination i8 lowered as is the r~sk of damaging the eggs through additiona} handling. Because all of th~ eggs in the chamber begin incubation at the same tim~it i8 not necessary to open and close thQ doors to remove chicks which have hatched from 60me of the eggs while adding new egg~ to being incubstion as in some prior art systems.
Because thQ chamber and air control unit are thoroughly cleansed between each incubation and hatching cycle, the risk 2~ of contamination i~ further reduced. In add~tion, all of the surfaces in the second plenum, i.e., hallways 98-104, can be thoroughly scrubbed several times a day if desired to further reduce the possibility of contamination. Because ~resh air is supplied to each cha~er, and vented therefrom, without the use of ducts, cleaning is much easier than is the case when ducts are present in which dirt, bacteria and the like tend to accumulate and thu~ increas~ the possibility of contamination.
Use of the ~gg trays and hatchery facility of the present invention thus increases thQ yield and quality of hatched chicks.
Having illustrated and described the principles of my in~ention in a preferred embodiment thereof, it should be readily apparent to those skilled in the art that the invention can be modified in arrangement and detail without departing ~ITI IT~: C~JFFT

-~-`! 2142293 WO 94/04~24 PCI~ 92/003~4 from su~h prislciples. I daim all ~odifisation~ c:oming within the ~pirit and s~ope of th~ ~ccompanying ~ laims.

:

SUBS~ITUTE SHEET

Claims (35)

I Claim:

1. A method for incubating and hatching eggs comprising the steps or placing a plurality of eggs on a horizontal egg support surface (22); provided with a plurality of curved surfaces (24, 26); positioning each egg so that the longitudinal axis or the egg forms an acute angle relative to the egg support surface (22) with the air-cell end of the egg being higher than the other end; characterized by:
providing said horizontal egg support surface (22) with a plurality of curved surfaces (24, 26);
immobilizing each egg relative to the egg support surface (22) in one of said curved surfaces (24, 26); and incubating the eggs until they hatch.

2. The method of claim 1 wherein the step or positioning each egg comprises the step of positioning each egg so that the longitudinal axis of the egg forms an angle of at least 20 degrees relative to the egg support surface (22).

3. The method of claim 2 wherein the step of positioning each egg comprises the step of positioning each egg so that the longitudinal axis of the egg forms an angle of approximately 35 degrees relative to the egg support surface (22).

4. The method of claim 1 wherein said method further includes the step of preventing the eggs from touching one another.

5. The method of claim 1 wherein said method further includes the step of tilting the egg support surface (22) during the step of incubating the eggs.

6. Apparatus for incubating and hatching eggs comprising means for supporting a plurality of eggs on a substantially planar egg support surface (22); characterized by egg supporting recesses (24, 26) provided on said substantially planar egg support surface (22) for holding each egg so that the longitudinal axis of the egg forms an acute angle relative to the egg support surface (22) with the air-cell end of the egg being further from the egg support surface (22) than the other end.

7. The apparatus of claim 6 wherein said holding means (24, 26) comprises means for holding each egg so that the longitudinal axis of the egg forms an angle of at least 20 degrees relative to the egg support surface (22).

8. The apparatus of claim 7 wherein said holding means (24, 26) comprises means for holding each egg so that the longitudinal axis of the egg forms an angle of approximately 35 degrees relative to the egg support surface (22).

9. The apparatus of claim 6 wherein said apparatus further includes means for preventing the eggs from touching one another.

10. The apparatus of claim 6 wherein said apparatus further includes means for tilting the egg support surface.

11. A tray for holding eggs during incubation and hatching comprising a bottom (12) having a surface (22) for supporting eggs; characterized by:
a plurality of curved surfaces (24, 26) formed on said bottom (12) each of which is constructed for holding an egg so that the longitudinal axis of the egg forms an acute angle relative to the bottom surface (22) with the air-cell end of the egg being further from the bottom surface than the other end.

12. The egg tray of claim 11 wherein said tray includes a side wall (14, 16, 18, 20) having an upwardly-directed interior shoulder (42, 43, 44) for supporting the bottom of another such tray in a nesting fashion.

13. The egg tray of claim 12 wherein said side wall (14, 16, 18, 20) includes air vents (58, 60) above said shoulder (42, 43, 44) for permitting a flow of air directly over eggs held by said curved surfaces (24, 26).

14. The egg tray of claim 12 wherein said shoulder (42, 43, 44) is constructed and arranged to space the upper surface of an egg received in a first tray from the lower surface of the bottom of a second tray stacked on and nested within said first tray.

15. The egg tray of claim 14 wherein said egg tray further includes means (52, 54) for guiding a first such egg tray into stacked and nested relation with a second such tray when said first tray is lowered onto said second tray.

16. The egg tray of claim 11 wherein said tray includes a side wall (14, 16, 18, 20) having a downwardly directed exterior shoulder (34, 36) for engaging a support in a tray rack.

17. A facility for incubating and hatching eggs comprising an egg incubating and hatching chamber (78, 80, 82) in which eggs are incubated and hatched; a first plenum (70, 72, 74, 76) in fluid communication with said chamber (78, 80, 82) for providing a flow of fresh air into said chamber (78, 80, 82); a second plenum (98, 100, 102, 104) in fluid communication with said chamber (78, 80, 82) for receiving a flow of used air from said chamber (78, 80, 82); a first sealable opening (106) between said first plenum (70, 72, 74, 76) and said chamber (78, 80, 82) said first opening (106) permitting a plurality of eggs to be moved from said first plenum (70, 72, 74, 76) into said chamber (78, 80, 82) when said first opening is unsealed;
characterized by:
a second sealable opening (108) between said second plenum (98, 100, 102, 104) and said chamber (78, 80, 82), said second opening (108) permitting a plurality of eggs to be moved from said chamber (78, 80, 82) into said second plenum (98, 100, 102, 104) when said second opening (108) is unsealed.

18. The facility of claim 17 wherein said facility further includes a plurality of said chambers (78, 80, 82), each being in fluid communication with said plenums (70, 72, 74, 76) (98, 100, 102, 104) and having such first (106) and second (108) sealable openings.

19. The facility of claim 17 wherein the pressure in said first plenum (70, 72, 74, 76) is maintained at a higher pressure than the pressure in said second plenum (98, 100, 102, 104).

20. The facility of claim 17 wherein said facility further includes a portable egg rack (84, 86) for moving a plurality of eggs into and out of said chamber (78, 80, 82) via said first (106) and second (108) openings, respectively.

21. The facility of claim 18 wherein said first (70, 72, 74, 76) and second (98, 100, 102, 104) plenums comprise first and second rooms.

22. A method for incubating and hatching eggs comprising the steps of providing fresh air to a first plenum (70, 72, 74, 76); loading an egg rack (84, 86) with a plurality of eggs moving the rack (84, 86) through the first plenum (70, 72, 74, 76) to an egg incubating and hatching chamber (78, 80, 82) in fluid communication with said first plenum (70, 72, 74, 76);
moving the rack (84, 86) from the first plenum (70, 72, 74, 76) into the chamber (78, 80, 82); incubating the eggs in the chamber (78, 80, 82) until the same are hatched; exhausting chamber (78, 80, 82) air into a second plenum (98, 100, 102, 104) during incubation and hatching; characterized by:
moving the rack (84, 86) from the chamber (78, 80, 82) into the second plenum (98, 100, 102, 104) after the eggs are hatched.

23. The method of claim 22 wherein said method further includes the step of maintaining the pressure in said first plenum (70, 72, 74, 76) higher than that in said second plenum (98, 100, 102, 104).

24. The method of claim 22 wherein said method further includes the step of periodically scrubbing and washing the second plenum (98, 100, 102, 104).

25. The method of claim 22 wherein the step of moving the rack (84, 86) from the first plenum (70, 72, 74, 76) into the chamber (78, 80, 82) comprises the steps of:
opening a first door (106) to the egg chamber (78, 80) 82);
moving the rack (84, 86) through the open door (106) into the chamber (78, 80, 82); and closing the first door (106).

2 6 . The method of claim 22 wherein the step of moving the rack (84, 86) from the chamber (78, 80, 82) into the second plenum (98, 100, 102, 104) after the eggs are hatched comprises the steps of:
opening a second door (108) to the egg chamber; and moving the rack (84, 86) through the open door (106) into the second plenum (98, 100, 102, 104).

27. The method of claim 26 wherein said method further includes the steps of:
moving the cleaning equipment through the second plenum (98, 100, 102, 104) and into the egg chamber (78, 80, 82) via the second door (108); and scrubbing and washing the egg chamber (78, 80, 82).

28. The method of claim 22 wherein said method further comprises the step of circulating hot and cold water through the chamber (78, 80, 82) for regulating chamber temperature during incubation.

29. The method of claim 28 wherein said method further includes the step of using the circulating water to provide heat for a building in which the chamber (78, 80, 82) is located.

30. A facility for incubating and hatching eggs comprising a first plenum (70, 72, 74, 76) filled with fresh air; an egg rack (84, 86); an egg incubating and hatching chamber (78, 80, 82); means for permitting rack movement (106) from said first plenum (70, 72, 74, 76) into said chamber (78, 80, 82); means for communicating fresh air (90) from said first plenum (70, 72, 74, 76) to said chamber (78, 80, 82) during egg incubation and hatching; a second plenum (98, 100, 102, 104); means for exhausting chamber air (94) into said second plenum (98, 100, 102, 104) during incubation and hatching; characterized by:
means for permitting rack movement (108) from said chamber (78, 80, 82) into said second plenum (98, 100, 102, 104) after incubation and hatching.

31. The facility of claim 30 wherein said means for permitting rack movement (106) from said first plenum (70, 72, 74, 76) into said chamber (78, 80, 82) comprises a door.

32. The facility of claim 30 wherein said means for permitting rack movement (108) from said chamber (78, 80, 82) into said second plenum (98, 100, 102, 104) after incubation and hatching comprises a door.

33. The facility of claim 30 wherein said facility further includes means for maintaining the pressure in said first plenum (70, 72, 74, 76) at a higher level than the pressure in said second plenum (98, 100, 102, 104).

34. The facility of claim 30 wherein said facility further includes means for circulating hot and cold water (88) through chamber (78, 80, 82) for regulating chamber temperature.

35. The facility of claim 34 wherein said facility further includes a heat exchanger (110) for extracting heat from water which has been circulated through said chamber (78, 80, 82) during egg incubation.