One of my rats had a litter about a month and a half ago. We finally put the babies with the father and everything was going fine.they have been in the same cage for about one week. He lets them run all over him and he plays with them but about 2 days ago my girlfriend had him out with one of the babies for a couple of hours. They were fine while they were out but when she put them back in the cage the father rat attacked the baby. He ripped out a chunk of flesh. He we then completely fine with the other babies and just let them play with him. The rat that was attacked did nothing to be attacked. What do you think the problem is. They are both now seperated the baby for healing purposes. The father is now in a cage alone because we dont want that to happen to any of the other babies.