Thats why i breed rats. Mice are down right disgusting to put it nicely. As far as rats, they are alot more social and will even nurse anothers babies if needed. One problem is you don't want more than one male in a breeding group (example 1 male-3 females). I like to separate my females when they are about to give birth so they can nurse without competition. My biggest problem with rats was Moms trying to hoard each others babies. Mice are just plain viscious. Rats rule in my book.