Patent Publication Number: US-2021185977-A1

Title: Disposable animal cage for use in ventilated rack

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a disposable animal cage which can be used in a ventilated or static caging rack system in which any corner or edge present in the interior of a cage base or cage top that is accessible to a rodent is defined by surfaces having a conical section or spline that is non-circular in order to prevent gnawing of the animal cage. 
     Description of Related Art 
     Systems for providing air and removing exhaust from racks containing animal cages are known. U.S. Pat. No. 5,307,757 describes a ventilated animal rack and animal cage system including a forced air system in which positive air is supplied by an air inlet manifold. Air is removed from the cage by negative air pressure to an exhaust manifold. The exhausted air is treated with a laboratory air treatment system or portable HEPA filtered exhaust unit and is released to the atmosphere. 
     U.S. Pat. No. 6,308,660 describes an animal caging system including a self-sealing or filtered opening animal cage removably connected to an air supply and an exhaust. The self-sealing or filtered opening animal cage is supported by a rack. The self-sealing or filtered opening animal cage is sealed by an air inlet connection and an air outlet connection to the air supply and the exhaust connection. After the cages are removed from the air supply and the exhaust, the air inlet connection and the exhaust connection seals the cage or has a filter media applied to the cage and top to prevent air from entering or exiting the cage. 
     The air supply and exhaust are provided with an air delivery and exhaust apparatus. The air delivery and exhaust apparatus is integrated with high efficiency particulate air (HEPA) filters. The air delivery and exhaust apparatus operates in a positive pressure mode for pushing air into the cage or in a negative mode for withdrawing air from the cage. Air from the environment is HEPA filtered and is used as supply air in the air delivery apparatus and exhaust air from the exhaust apparatus is HEPA filtered before being emitted into the environment. The animal caging system provides isolation of the animal cage and provides containment of airborne pathogens within the caging system. 
     Animal containment systems that comprise disposable, single-use components, which do not require washing and sterilization for re-use are known. U.S. Pat. No. 9,265,229 describes a single use cage preventing gnawing damage to the thin walled cage by including a geometric guidelines for the interior corners of the cage. 
     It is desirable to provide an improved geometric design of a disposable animal cage which prevents animals from gnawing on the cage surfaces and having low manufacturing costs. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a disposable animal cage which can be used in a ventilated or static caging rack system. The animal cage can be a free-standing cage assembly constructed of a cage base and a cage top. The animal cage can be used with rodent animals or similar sized species. 
     The cage base comprises walls extending from a floor. The walls can be integral with the floor. The cage top comprises walls extending from a ceiling or a flat top. The cage base and the cage top can be constructed of a polymer. Any or all walls and the floor of the cage base can have a material thickness between about 0.005 inches to about 0.125 inches. Any or all walls of the cage top can have a material thickness between about 0.005 inches to about 0.125 inches. 
     Any corner or edge present in the interior of the cage assembly of the cage base or the cage top that is accessible to a rodent that can be contained in the cage is defined by surfaces having an angle greater than or equal to 180 degrees and less than or equal to 360 degrees. Any corner or edge present in the interior of the cage assembly of the cage base or the cage top that is accessible to a rodent that can be contained in the cage can be defined by surfaces having a conical section which is non-circular. A conical section can be formed in a wall of the cage base toward the interior of the cage base. For example, the conical section can be a parabola, ellipse, hyperbola or spline. The design of the animal cage having a corner, wall or edge in the interior of the cage assembly with a conical section or spline can prevent an animal from gnawing the cage base or the cage top. 
     The cage top can include a water housing mount pocket. The water housing mount pocket receives a container. The container includes an aperture. The aperture can be formed within a cap of the container. An aperture in the water housing mount pocket can permit access by the animal to the aperture of the container received within the water housing mount/pocket. The aperture of the container can be licked by the animal to dispense water stored within the container. The water housing mount pocket can have a conical or spline shape to prevent an animal from gnawing the water housing mount pocket and the container. 
     A feed tray can include side walls angled toward feed aperture. An edge of the feed tray can be received in a depression of the cage base for removably attaching the feed tray to the cage base. The feed tray can be disposed beneath an air filter of the cage top. The feed tray location within the animal cage provides protection of the filter from being gnawed or punctured and prevents escape of the animals from the animal cage. 
     The cage base and cage top can be snap fitted to one another. A top edge of the cage base extending from the cage base creates a suspended runner system allowing the animal cage to be installed on rows of a ventilated rack or a static air rack to automatically lock the cage top and cage base together. 
     In one embodiment, a plurality of apertures are positioned in a side wall of the cage base and the cage top. Filter media can be positioned over the plurality of apertures. In this embodiment, an air inlet port can be placed adjacent the filter media to allow air to flow from the air inlet port into the cage through the small apertures of the cage base. An air exhaust port can be placed adjacent the filter media to allow air to flow from the cage to the air exhaust port through the small apertures of the cage top. 
     The cage and/or cage top can include a plurality of small apertures in close proximity to one another. The top is formed of a flat ceiling with walls extending from the ceiling. The structure prevents animals from chewing, scratching or altering the plastic cage and/or cage top to prevent escaping animals as well as protect the filter media while allowing air to exchange between the cage assembly by forced air or natural flow methods. The small apertures can be manufactured by removing material from the cage and/or cage top from inside of the cage and/or cage top towards the outside of the cage and/or cage top such that any burr created during the manufacturing process is positioned on an outside surface of the cage/top. Alternatively, the small apertures can be manufactured by removing material from the cage/top from outside of the cage and/or cage top towards the inside of the cage such that any burr created during the manufacturing process is positioned at a portion of the cage which is inaccessible by an animal received in the cage. The cage can be used in a ventilated or static embodiment. 
     The cage base can be counter bowed to strengthen the cage base. The strengthened cage base can reduce or eliminate sagging of the cage base caused by weight of bedding, animal(s) or excretion by the animal(s). 
     In one embodiment, the cage top can include a pair of water housing mount pockets for receiving respective water containers. The cage top can include one or more openings for ventilation. The one or more openings can be covered by a filter media. A structure including a front section and a rear section is configured to be received under the cage top, The front section being positioned below the water housing mount pockets and the rear section being positioned below the one or more openings, The structure can be formed of a plurality of wires or sheet metal in a frame configuration. 
     The invention will be more fully described by reference to the following drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  illustrates a perspective view of an animal cage assembly in accordance with the teachings of the present invention. 
         FIG. 1B  illustrates a perspective view of an animal cage assembly before being assembled in accordance with the teachings of the present invention. 
         FIG. 2  illustrates an isometric view of a base of the cage shown in  FIG. 1B . 
         FIG. 3  illustrates a top isometric view of a top of the cage shown in  FIG. 1B . 
         FIG. 4  illustrates a bottom isometric view of the top of the cage shown in  FIG. 1B . 
         FIG. 5A  illustrates a top isometric view of a water housing used in the animal cage assembly shown in  FIG. 1B . 
         FIG. 5B  illustrates a illustrates a bottom isometric view of a water housing shown in  FIG. 1B . 
         FIG. 6  illustrates an isometric view of a feed tray used in the animal cage assembly shown in  FIG. 1B . 
         FIG. 7  illustrates a side cross-section view of the base of the cage shown in  FIG. 1B . 
         FIG. 8A  is a schematic diagram of shapes which can be used with surfaces of the cage. 
         FIG. 8B  is a partial side view of the base of the cage including a hyperbola surface. 
         FIG. 9  is a schematic diagram of a plurality of the cage assemblies of the present invention used in a ventilated rack and or a static rack. 
         FIG. 10  is a schematic diagram of the cage assembly shown in  FIG. 1A  including a connection to an inlet air and an exhaust. 
         FIG. 11A  illustrates a perspective view of an animal cage assembly in accordance with the teachings of the present invention. 
         FIG. 11B  illustrates a perspective view of the animal cage assembly shown in  FIG. 11A  before being assembled in accordance with the teachings of the present invention. 
         FIG. 11C  illustrates an isometric view of a base of the cage shown in  FIG. 11A . 
         FIG. 11D  illustrates a top isometric view of a top of the cage shown in  FIG. 11A . 
         FIG. 12  is a schematic diagram of the cage assembly shown in  FIG. 11A  including a connection to an inlet air and an exhaust. 
         FIG. 13A  illustrates a perspective view of an animal cage assembly in accordance with the teachings of the present invention. 
         FIG. 13B  illustrates a bottom view of the cage top shown in  FIG. 13A . 
         FIG. 14  illustrates a perspective view of an animal cage assembly in accordance with the teachings of the present invention. 
         FIG. 15A  illustrates a perspective view of the animal cage assembly before being assembled in accordance with the teachings of the present invention. 
         FIG. 15B  illustrates a cross sectional view of the animal cage assembly shown in  FIG. 15A . 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in greater detail to a preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings and the description to refer to the same or like parts. 
       FIGS. 1A-1B  illustrate cage assembly  10  in accordance with the teachings of the present invention including cage  11 . Cage  11  includes cage base  13  and cage top  20  as shown in  FIG. 1A . 
     Water housing mount pocket  30  is formed in cage top  20 . Water housing  40  is removably received in water housing mount pocket  30 . Feed tray  50  is removably supported by top edge  14  of cage base  13  as shown in  FIG. 1B . Card holder  60  is removably coupled to lip  19  of cage base  13 . 
     Cage base  13  includes walls  16  extending from floor  17  as shown in  FIG. 2 . Walls  16  and floor  17  can be integral to one another. Walls  16  can include side walls  16   a  and  16   b  on either side of cage base  13 . Walls  16  can include front wall  16   c  and rear wall  16   d.  Top edge  14  of side walls  16   a  and  16   b  can include depressions  18 . Walls  16  of cage base  13  support cage top  20  on top edge  14  as shown in  FIG. 1A . Cage base  13  and cage top  20  can be snap fitted to one another. Top edge  14  of cage base  13  extends from cage base  13 . 
     Referring to  FIG. 2 , lip  12  can extend around cage base  13  below top edge  14 . Lip  12  can include card holder mount apertures  15  or slide protrusion. Edge junction  18  can be formed between adjacent walls  16 . For example, edge junction  18  can be formed respectively between side wall  16   a  and front wall  16   c  and side wall  16   a  and rear wall  16   d.  Edge junction  18  can be formed respectively between side wall  16   b  and front wall  16   c  and side wall  16   b  and rear wall  16   d.  Corner junction  19  can be formed between adjacent walls  16  and floor  17 . For example, corner junction  19  can be formed respectively between: side wall  16   a,  front wall  16   c  and floor  17 ; side wall  16   a,  rear wall  16   d  and floor  17 ; side wall  16   b,  front wall  16   c  and floor  17 ; and side wall  16   b,  rear wall  16   d  and floor  17 . 
     Referring to  FIGS. 3 and 4 , cage top  20  includes walls  21  extending from ceiling  22 . Walls  21  and ceiling  22  can be integral to one another. Walls  21  may or may not include side walls  21   a  and  21   b  on either side of cage top  20 . Walls  21  may or may not include front wall  21   c  and rear wall  21   d.  One or more openings  23  can be formed in ceiling  22 . One or more openings  23  can be covered by one or more filters  24 . One or more openings  23  can be used to receive air. Air exhaust port  25  can be formed or punched in rear wall  21   d  or ceiling  22  of cage top  20  as shown in  FIG. 4 . 
     Edge junction  28  can be formed between adjacent walls  21  as shown in  FIG. 4 . For example, edge junction  28  can be formed respectively between side wall  21   a  and front wall  21   c  and side wall  21   a  and rear wall  21   d.  Edge junction  28  can be formed respectively between side wall  21   b  and front wall  21   c  and side wall  21   b  and rear wall  21   d.  Corner junction  29  can be formed between adjacent walls  21  and ceiling  22 . For example, corner junction  29  can be formed respectively between: side wall  21   a,  front wall  21   c  and ceiling  22 ; side wall  21   a,  rear wall  21   d  and ceiling  22 ; side wall  21   b,  front wall  21   c  and ceiling  22 ; and side wall  21   b,  rear wall  21   d  and ceiling  22 . 
     Water housing mount pocket  30  includes conical support  32 . Conical support  32  includes bottom end  33 , lower end  34  and upper end  35 . Lower end  34  extends to bottom end  33 . Conical section  36  is positioned at lower end  34  to extend between bottom end  33  and upper end  35 . Bottom end  33  can be substantially flat. Aperture  37  is formed or punched in bottom end  33 . 
     Cage base  13  and cage top  20  can be constructed of a polymer. Suitable polymer materials include, but not limited to polyethylene terephthalate. Any or all walls  16  and floor  17  of cage base  13  can have a material thickness between about 0.005 inches to about 0.125 inches. Any or all walls  21  and ceiling  22  of cage top  20  can have a material thickness between about 0.005 inches to about 0.125 inches. 
     Water housing  40  can include container  42  as shown in  FIGS. 5A-5B . Container  42  can have wall or walls  43  extending from bottom  44  to neck  45 . Container  42  can be used to house water. In one embodiment, container  42  can have a bottle shape. Cap  46  is removably attached to top lip  48  of neck  45 . Cap  46  can have aperture  47 . During use, water housing  40  is inverted and to allow cap  46  to be received in water housing mount pocket  30 . Aperture  47  of cap  46  is aligned with aperture  37  of water housing mount pocket  30  as shown in  FIG. 7 . An animal can lick through aperture  37  to reach aperture of  47  of cap  46  in order to receive water retained in container  42 . 
     Referring to  FIG. 6 , feed tray  50  includes walls  51  extending from floor  52 . Walls  51  can include side walls  51   a  and  51   b  on either side of feed tray  50 . Walls  51  can include front wall  51   c  and rear wall  51   d.  Section  54  of floor  52  adjacent side walls  51   a  and  51   b  can be angled by Angle A 1  toward feed apertures  53 . Lip  55  can extend from top edge  56  of feed tray  50 . Top  57  of lip  55  can be angled by Angle A 2  to edge  58  of lip  55 . Edge  58  can be curved. Edge  58  of feed tray  50  can be received in depression  59  of cage base  13  for removably attaching feed tray  50  to cage base  13  as shown in  FIG. 1B . Depression of  59  can be positioned adjacent one or more filters  24  to allow feed tray  50  to be positioned underneath one or more filters  24  when feed tray  50 , cage base  13  and cage top  20  are assembled as shown in  FIG. 1B . 
     Referring to  FIGS. 1A and 1B , mount projections  61  of card holder  60  can be received in card holder mount apertures  15  of lip  12  of cage base  13  to attach card holder  60  to cage base  13 . Card holder  60  includes lip projections  65 . Lip projections  65  can be used to retain a card (not shown) identifying the cage and/or animals within the cage. 
     Referring to  FIG. 7 , each edge junction  18  or corner junction  19  of wall or walls  16  and/or floor  17  that are accessible to a rodent that can be contained in cage  11  are defined by surfaces having an angle greater than or equal to about 180 degrees and less than or equal to about 360 degrees(180≤σ≤360). Each edge junction  18  or corner junction  19  of wall or walls  16  and/or floor  17  that are accessible to a rodent that can be contained in cage  11  can be defined by surfaces with a conical shape. Each edge junction  28  or corner junction  29  of wall or walls  21  and/or ceiling  22  that are accessible to a rodent that can be contained in cage  11  are defined by surfaces having an angle greater than or equal to about 180 degrees and less than or equal to about 360 degrees (180≤σ≤360). Each edge junction  28  or corner junction  29  of wall or walls  21  and/or ceiling  22  that are accessible to a rodent that can be contained in cage  11  can be defined by surfaces having a conical shape. For example, the conical shape can be a parabola, ellipse, hyperbola or spline. 
     Cage base  13  includes conical section  70  formed in rear wall  16   d  toward interior  75  of cage base  13 . Conical section  70  is positioned to extend between bottom end  71  and upper end  72  of rear wall  16   d.  Conical section  70  can have a conical shape of a parabola, ellipse, hyperbola or spline as shown in  FIG. 8A . 
     Referring to  FIG. 7 , cage top  20  includes conical section  80  formed in ceiling  22 . Conical section  80  is positioned to extend between rear section  81  adjacent to rear wall  21   d  and mid-section  82  of ceiling  22 . Conical section  80  can have a conical shape of a parabola, ellipse, hyperbola or spline as shown in  FIG. 8A . 
     Referring to  FIG. 7 , cage top  20  includes water housing mount pocket  30  including conical section  36 . Conical section  36  can have a conical shape of a parabola, ellipse, hyperbola or spline as shown in  FIG. 8A . 
     In one embodiment, conical section  70  formed in cage base  13  can be formed in the shape of a hyperbola as shown in  FIG. 8B . 
       FIG. 9  shows an embodiment of animal cage system  100 . Individual cages  11  are supported on at least one shelf, platform or suspended runner system  103  on rows  105  of rack  104 . Cage base  13  and cage top  20  can be snap fitted to one another. Top edge  14  of cage base  13  extending from cage base  13  can be received within suspended runner system  103  for automatically locking cage base  13  and cage top  20  together. Animal cage system  100  can be a ventilated rack or a static air rack. Example animal cage racks are manufactured by Allentown, Inc. as Nexgen, Micro-Vent and PNC. 
       FIG. 10  illustrates air delivery and exhaust which can be used with animal cage system  100  to provide a ventilated rack. Nozzle  110  can be received or positioned adjacent air inlet port  111  shown in  FIG. 2 . Referring to  FIG. 10 , filter  112  can cover air inlet port  111 . Nozzle  110  includes at least one air opening  113  formed in end  114  of nozzle  110  for emitting air  118  from air inlet plenum  119  through inlet  120  into cage  11  in the direction of arrow A i . Air  118  circulates within cage  11  and exits cage  11  in the direction of arrow A o  as exhaust  120  through exhaust plenum  121 . Exhaust plenum  121  can be coupled or adjacent to air exhaust port  25  of cage top  20 . 
     Referring to  FIG. 9 , at least one supply blower or equivalent can be coupled rack air input port  130  and at least one exhaust blower or equivalent can be coupled to rack exhaust port  140  for supplying air to rack  104  and removing exhaust from rack  104 . Alternatively air delivery and exhaust apparatus can supply and exhaust air via wall mounted or tower blower ventilation system, such as one manufactured by Allentown Inc. as an EcoFlo Rack, EcoFlo Tower, or EcoFlo Halo. Alternatively air delivery and exhaust apparatus can be supplied by an above ceiling or remotely mounted air supply device such as one manufactured by Allentown Inc. Eco Flo Interstitial Blower while using the facility available exhaust system to exhaust the rack such as demonstrated in the Allentown Inc system FIAS (Facility Integrated Airflow Solutions). 
       FIGS. 11A-11D  and  FIG. 12  illustrate an alternate embodiment of cage assembly  200  in which items shown with the same reference numerals from  FIG. 1A - FIG. 10  are the same. Cage assembly  200  includes lip  212  which extends around cage bottom  213  below top portion  214 . One or more grooves  215  can be formed in lip  212 . Card holder  300  replaces card holder  50  shown in  FIG. 1A . Card holder  300  includes base  313 . Flange  316  and flange  317  extend from rear  318  of base  313 . Clip card holder  319  extends from front  320  of base  313 . Flange  316  and flange  317  can slide over lip  212  to attach card holder  300  to cage assembly  200 . 
       FIGS. 13A-13B  illustrate cage assembly  400  in accordance with the teachings of the present invention including cage  411  in which items shown with the same reference numerals from  FIG. 1A - FIG. 12  are the same. Cage assembly  400  can be a static cage or ventilated cage. Cage  411  includes cage base  13  and cage top  420 . Water housing mount pocket  30  is formed in cage top  420 . Water housing  40  is removably received in water housing mount pocket  30 . 
     Cage top  420  includes walls  421  extending from ceiling  422 . Walls  421  and ceiling  422  can be integral to one another. Ceiling  422  can be substantially flat. Walls  421  may or may not include side walls  421   a  and  421   b  on either side of cage top  420 . Walls  421  may or may not include front wall  421   c  and rear wall  421   d.  Edge junction  428  can be formed between adjacent walls  421 . For example, edge junction  428  can be formed respectively between side wall  421   a  and front wall  421   c  and side wall  421   a  and rear wall  421   d.  Edge junction  428  can be formed respectively between side wall  421   b  and front wall  421   c  and side wall  421   b  and rear wall  421   d.  Corner junction  429  can be formed between adjacent walls  421  and ceiling  422 . For example, corner junction  429  can be formed respectively between: side wall  421   a,  front wall  421   c  and ceiling  422 ; side wall  421   a,  rear wall  421   d  and ceiling  422 ; side wall  421   b,  front wall  421   c  and ceiling  242 ; and side wall  421   b,  rear wall  421   d  and ceiling  422 . 
     One or more openings  23  can be formed in ceiling  422 . One or more openings  23  can be covered by one or more filters  24 . One or more openings  23  can be used to to receive and exhaust air for ventilation of cage  411 . 
     Ceiling  422  can include perforation section  430 . Perforation section  430  includes a plurality of apertures  435 . Apertures  435  are within close proximity to each other. Apertures  435  can be small. In one embodiment, apertures  435  can have a size in the range of about 0.031 to about 0.125 inches and a spacing between apertures  435  in the range of about 0.031 to about 0.125 inches. In one embodiment, apertures  435  can have a size in the range of about 0.0625 to about 0.125 inches and a spacing between apertures  435  in the range of about 0.0625 to about 0.125 inches. 
     Apertures  435  can be manufactured by being drilled, milled, punched or any other method of removing material from ceiling  422 . In one embodiment, apertures  435  are formed from inside surface  437  to outside surface  439  of cage top  420 . One or more burrs  440  may be formed on outside surface  439  of cage top  420  during removal of material from ceiling  422  as shown in  FIG. 13A . 
     Alternatively, apertures  435  are formed from outside surface  439  to inside surface  437  of cage top  420 . One or more burrs  440  can be formed on inside surface  437  of cage top  420 . In this embodiment, perforation section  430  is located in an area which is difficult for the animal access as shown in  FIG. 13B . In alternative embodiments perforation section  430  can be located at other locations of cage base  13  and cage top  420  for example walls  421  and walls  16 . 
       FIG. 14  illustrates cage assembly  500  in accordance with the teachings of the present invention including cage  511 . Cage  511  includes cage base  513  and cage top  520 . For example, cage  511  can be used to house rats. Cage top  520  includes walls  521  extending from ceiling  522 . Walls  521  and ceiling  522  can be integral to one another. Walls  521  may or may not include side walls  521   a  and  521   b  on either side of cage top  520 . Walls  521  may or may not include front wall  521   c  and rear wall  521   d.  One or Openings  523   a  and  523   b  can be formed in ceiling  522 . Openings  523   a  and  523   b  can be covered by one or more filters  524 . 
     Water housing mount pocket  530   a  and water housing mount pocket  530   b  are formed in cage top  420  in a lateral side by side configuration. Water housing mount pocket  530   a  can be positioned adjacent opening  523   a.  Water housing mount pocket  530   b  can be positioned adjacent opening  523   b.  Water housing  540   a  is removably received in water housing mount pocket  530   a.  Water housing  540   b  is removably received in water mount pocket  530   b.    
     Referring to  FIG. 15A , in an alternate embodiment, water housing mount pocket  530   a  and water housing mount pocket  530   b  can be formed in cage top  420  in a longitudinal side by side configuration. Water housing mount pocket  530   a  and water housing mount pocket  530   b  can be positioned on the same side as opening  523   a.  Water housing mount pocket  530   a  can be positioned adjacent opening  523   a.  Water housing mount pocket  530   b  is positioned adjacent wall  521   c  in front of water housing mount pocket  530   a.  Water housing  540   a  is removably received in water housing mount pocket  530   a.  Water housing  540   b  is removably received in water mount pocket  530   b.    
     Cage base  513  includes walls  516  extending from floor  517 . Walls  516  and floor  517  can be integral to one another. Walls  516  can include side walls  516   a  and  516   b  on either side of cage base  513 . Walls  516  can include front wall  516   c  and rear wall  516   d.  Top edge  514  of side walls  516   a  and  516   b  can include depressions  518 . Edge junction  518  can be formed between adjacent walls  516 . For example, edge junction  518  can be formed respectively between side wall  516   a  and front wall  516   c  and side wall  516   a  and rear wall  516   d.  Edge junction  518  can be formed respectively between side wall  516   b  and front wall  516   c  and side wall  516   b  and rear wall  516   d.  Corner junction  519  can be formed between adjacent walls  516  and floor  517 . For example, corner junction  519  can be formed respectively between: side wall  516   a,  front wall  516   c  and floor  517 ; side wall  516   a,  rear wall  516   d  and floor  517 ; side wall  516   b,  front wall  516   c  and floor  517 ; and side wall  516   b,  rear wall  516   d  and floor  517 . 
     Edge junction  528  can be formed between adjacent walls  521 . For example, edge junction  528  can be formed respectively between side wall  521   a  and front wall  521   c  and side wall  521   a  and rear wall  521   d.  Edge junction  528  can be formed respectively between side wall  521   b  and front wall  521   c  and side wall  521   b  and rear wall  521   d.  Corner junction  529  can be formed between adjacent walls  521  and ceiling  522 . For example, corner junction  529  can be formed respectively between: side wall  521   a,  front wall  521   c  and ceiling  522 ; side wall  521   a,  rear wall  521   d  and ceiling  522 ; side wall  521   b,  front wall  521   c  and ceiling  522 ; and side wall  521   b,  rear wall  521   d  and ceiling  522 . 
     Structure  570  can include front section  572  and rear section  574 . Middle section  575  can join front section  572  to rear section  574 . Front section  574  includes side walls  581   a  and  581   b  extending from bottom  583 . Front wall  581   c  extends from bottom  583 . Rear section  574  includes side walls  591   a  and  591   b  extending from top  593 . Rear wall  591   c  extends from top  593 . Front section  572 , rear section  574  and middle section  575  can be formed of a plurality of wires  596  in a side by side configuration. Alternatively, structure  570  can be formed of sheet metal in a frame configuration. Front section  572  extends below water mount housing mount pockets  530   a  and  530   b.  Rear section  574  extends below opening  523   a  and  523   b.  Front section  572  and rear section  574  prevent animals from reaching or gnawing on water mount pockets  530   a  and  530   b  and openings  523   a  and  523   b.    
     Flange  578  can extend laterally from side wall  591   a  and  591   b.  Flanges  578  extending from side wall  591   a  and side wall  591   b  can be received in depressions  518  of respective side wall  516   a  and side wall  516   b  as shown in  FIG. 15B  for supporting structure  570 . Cage top  520  can be received over structure  570 . Walls  516  of cage base  513  support cage top  520  and structure  570  on top edge  514 . Cage bottom  513  can be counter bowed a distance of D 1  to strengthen cage bottom  513  and minimize or eliminate sagging. 
     Air inlet port  551  can include a plurality of apertures  555  for receiving incoming air when used in combination with air delivery and exhaust system  100  as shown in  FIG. 9 . Referring to  FIG. 15B , filter  512  can cover air inlet port  511 . 
     It is to be understood that the above-described embodiments are illustrative of only a few of the many possible specific embodiments, which can represent applications of the principles of the invention. Numerous and varied other arrangements can be readily devised in accordance with these principles by those skilled in the art without departing from the spirit and scope of the invention.