Anyone who moved there could bring any pets they had with them - they were usually dogs and cats, but I remember my grandmother telling me about a guy who brought his horse. They found a place nearby to board him so the man could visit. The only rule was that they couldn't replace them when they passed on. It might have been a problem if 90-year-olds got a kitten or puppy. Though I do remember one time when the community adopted a cat who had kittens. The woodworking hobbyists fashioned a special home for mother and kittens which had a glass roof so residents could look in on them. And afterwards the cat and kittens all found homes within the community.
And in the assisted living sections - two levels where residents who needed more care lived - there was a program called Noah's Oasis. There were dogs or cats who lived on each hall and visited with those who became "patients." When my grandmother had to give up her apartment and move there, two rescue dogs lived on her hall and were very popular. Besides that, my grandmother "rented" a bird. It was her bird, but someone came in daily to clean the cage and feed "Amelia." She just enjoyed the company.
I visited a lot, got to know the pups and the bird, and when my grandmother passed away, I spoke at her "memorial service" there and that was what I talked about - my grandmother is the reason that my whole extended family loves animals and being able to keep pets made it a desirable place to live, or visit, for that matter.