MICE

I had my own rattery for quite a few years.. rats are not so bad, they are easy to care for, way less stinky than mice, and as far as them eating thier babies... I never had alot of problems with it... every once in awhile you get a rogue female who is into eating babies, you just feed her off, males will eat babies that are not thiers- not sure how they know which babies are not theirs, but they seem to know. And if you do handle them enough, makes baby retrieval easier... I currently have a few dumbo eared rats for pets and some standards for breeders, I fed off all my mice- they STINK...

Also- after a female is over 9 months old, if she has not been bred before- I dont suggest it cause then they can die trying to birth.

Everyone is dead-right with the smell issue. I have had mice, and there's always that horrible scent they give off. But my current breeder rats are not that bad at all. Once a week, I do a full cage cleanout/bleaching (except when the female has babies, then I just clean out everything but the nest, and do not bleach.) I have three 10-g tanks; one female in each, and one extra for the male when he is not breeding. I leave him in with each female for a few days, and they mate.
Just make sure that for rats, your cages are securely lidded. And if you use a wire cage, make sure the wires are not so wide apart that a baby could squeeze out.