I have 4 fancy rats. 2 hairless and 2 normal hooded. The hairless are the funniest ones of the group. We got Mama, our elderly one, as an adult and she's the sweetest rat I have ever come across. Loves to lick and jump from my shoulder to my boyfriend's shoulder and vice versa. Never get any live feeders or pet rats from Petco... They have a parasite problem. Our first rat we got there, a little girl, had tapeworms and coccidia. This little feeder mouse I "saved" from being eaten, has pinworms and who knows what else, I didn't both looking through the whole fecal slide. The little girl rat is the same age as our hairless male. He's huge and almost full grown, but she's half his size. So I'm thinking that having parasites and a bad diet(they were feeding an alfalfa-based diet-which they can't digest for anything) early on caused her growth to be halted. Frozen feeders you won't have problems with, just make sure they're frozen for at least 30 days or so. Sorry for venting, it's just that Petco here and in Temple are both the biggest rip-offs I've ever seen. Grrr...