We have 2 dogs. My kids are supposed to feed them. But I usually end up doing it. We also have chickens and ducks. My 11 year old feeds them. He's proud to take care of them and watch them grow.
We have a kitten and a hamster. I take care of them because, IMO, the boys are still too young to take care of them by doing things like cleaning cages, litter boxes and the feeding.
We have a Dog,Cat,Hampster and a Ferret... Both my DS and I take care of the animals. I do it when he is with his dad and he does most of it when he is with me :)