All primary enclosures for dogs and cats shall conform to the following requirements:

1. (A) General.

   1. (1) Requirements for primary enclosures for dogs and cats. Primary enclosures shall be structurally sound, maintained in good repair to protect the dogs and cats from injury and provide for their health and comfort, to contain them, and to keep predators out.
   2. (2) Primary enclosures shallbe constructed and maintained so as to enable the dogs and cats to remain dry and clean.
   3. (3) Primary enclosures shall be constructed and maintained so that the dogs and cats contained therein have convenient access to clean food and water as required in 105 CMR 910.000.
   4. (4) The floors of the primary enclosures shall be constructed so as to protect the dogs' and cats' feet and legs from injury.

2. (B) Additional requirements for primary enclosures housing cats.

   1. (1) In all enclosures having a solid floor, a receptacle containing sufficient clean litter shall be provided to contain excreta.
   2. (2) Each primary enclosure shall be provided with a solid resting surface or surfaces which, in the aggregate, shall be of adequate size to comfortably hold all occupants of the primary enclosures at the same time. Such resting surface or surfaces shall be elevated in primary enclosures housing two or more cats, and shall be adequate to hold all occupants at the same time.

3. (C) Space requirements.

   1. (1) Dogs and cats. Primary enclosures shall be constructed and maintained so as to provide sufficient space to allow each dog and cat to turn about freely and to easily stand, sit, lie, and stretch in a comfortable normal position.

   2. (2) Dogs. In addition to the provisions of 105 CMR 910.103(C)(1), each dog housed in any primary enclosure shall be provided with a minimum square footage of floor space as required by the regulations implementing the Animal Welfare Act. This required floor space is equal to the mathematical square of the sum of the length of the dog in inches, as measured from the tip of its nose to the base of its tail, plus six inches, expressed in square feet. No more than 12 adult compatible unconditioned dogs shall be housed in the same primary enclosure. This requirement may be computed by using the following equation:

      (length of dog in inches + 6) x (length of dog in inches + 6) =

      (required area in square inches) =

      144

   required square feet of floor space. These requirements may require modifications according to the body conformation of particular breeds. If the federal regulation is amended to include a larger cage size, that provision shall supersede the above. (3) Dog houses with chains. If dog houses with chains are used as primary enclosures for dogs kept outdoors, the chains used shall be so placed or attached that they cannot become entangled with the chains of other dogs or any other objects. Such chains shall be of a type commonly used for the size dogs involved and shall be attached to the dog by means of a well-fitted collar. Such chains shall be at least three times the length of the dog as measured fromthe tip of its nose to the base of its tail and shall allow the dog convenient access to the dog house. (4) Cats. In addition to the provision of 105 CMR 910.103(C)(1) each adult cat housed in any primary enclosure shall be provided with space the size required by the regulations implementing the AnimalWelfare Act. The required space is a minimum of 2½ square feet of floor space. Not more than 12 adult unconditioned cats shall be housed in the same primary enclosure. If the federal regulation is amended to include a larger cage size, that provision shall supersede the above.

4. (D) Exercise. Each research institution shall ensure that each dog is allowed the opportunity to exercise at regular intervals, but in no event less than once a day.