I got somewhat lucky with my petstore pigs. They were both healthy, yet mis-sexed.
We started out with 2 "girls", ended up with 7.
Just a few weeks ago, I stopped by in a brand new Petco to look around. They had a beautiful New Zealand White rabbit who had horrible hair loss and a URI. When I brought it to the store's attention, she said he came from the place that way and "he was under observation" yet still for sale.