Any thoughts on an explanation for this? After the birthing last feb, my rat colony started to decline. Had a litter from a naked female and a regular female and since naked females don't nurse I fed off most of the babies and put the remainder with the regular female to nurse. Most the babies ended up dieing and those that survived got gassed and fed. Had saved one male to replace the naked male that was formerly used for breeding. No big deal at this point, just keep breeding. It shouldn't have taken him 3 months to get a female pregnant, but 6 months later none were pregnant yet. 6 Months with no births meant I was running low on rats. The colony got down to 5 females (usually have double that), the male, and nearly out of frozen rats. In September I decided to get a new male from the petshop since the current one isn't doing his job. Put the new male in with 2 females and a few weeks ago they gave birth so I fed off the old male. Put the new male in with 2 other females to get them pregnant as well. Seems like all is going well. The rats are getting pregnant so I'll be able to build up a stock of frozen rats of various sizes again. Yesterday I lost one of the nursing females. The other female ate her stomach. Now she's going to be stuck with both litters of babies which were already on the scrawny side since one wasn't nursing much. This morning the pet shop male died. The 2 females he was in with ate his brain. Now have no males. There was no sounds of fighting (light sleeper) and they were well fed and cared for. They are considered pets up until they get gassed so are treated nicely. Handled, cleaned, given treats. Pretty much spoil them with kindness to keep them happy and calm. This colony has been going for 5 years with rarely an issue of fighting and no cannibalism, now this year it seems to be failing. Any time I did see rats fighting they would get gassed as I want to keep aggression at a minimum. The 3 females that were involved in these recent killings would get gassed if not for being pregnant/nursing. But that would leave me with 1 female rat and 2 litters of babies with no mom. What would any of you do in this situation? I'm considering just gassing them all and starting fresh with new rats. Or can anybody think of a reason as to why it would fail after running strong for 5 years? Should I try to salvage it? Have 2 litters, a pregnant female, and 2 possibly pregnant females.