Asia's largest shelter for cats has put them on a vegan diet (read story). I visited Karuna Kunj, an animal shelter outside of Kolkata (Calcutta), which is run by Compassionate Crusaders Trust, last year. At that time there were about 80 or so cats waiting for adoption. Oddly, most every one was primarily white with a big round head as seen in this photo I took when I was there.

As described in the article the cats have an enriched space. From the large, enclosed space, there are passages to wire-mesh enclosed outdoor areas and lots of logs, tunnels, perches for the cats to play and lounge on. Plus, I was told that these items are moved around now and then so that the cats don't get bored.