I have always heard to feed off the ones who you find out are giving you problems, get rid of the bad apples so to speak. My problem is, I have a rack with 1.4 in each tub and every now and then I will go in there and a rat will be dead and partially eaten, problem is, I can't figure out which one is doing it, if not more than one. I hear if you get rid of the bad apples then you can get a healthier collection and don't have to worry about those problems.