I have a tank of rats(they chewed their bin but I needed them as breeders at the time, so moved them to glass tank) that I watch. They get treats(more than the regular rats) and I play with them and fuss over them. The offspring are feeders.

I feel it's the same as ranching. Just because the animals are going to be food at some point doesn't mean you can't enjoy them, treat them well and make them happy until "the day".