Chewed Up Mommy Rat???

[Batdad]

Hello All

I am trying to get my rats back up and breeding as we settle in to our new home (moved 600+ Miles). I had a strange one tonight and don’t quite understand it and I need some advice.

Short history: I had four colonies, two of 1:3 and two of 1:2 in concrete mixing bins 16”x22”. I found that the 1:3 colonies seemed a little crowded, especially with babies, and got dirty a lot faster, so I went and got another male and now have 5 colonies of 1:2. One of the colonies that I took one of the females from has about fifteen pups from multiple litters and I was fairly sure that the female removed was not one of the birth mothers (at least of the younger pups).

Strange event: When I checked in on the rats tonight the largest female in with the fifteen pups had half of her muzzle chewed off.

Problem/Question: She doesn’t look good (laboured breathing). She was still feeding the pups but, I don’t thinking she is going to survive. What could have caused this, any guesses? They have plenty of food (high in protein) and water, and are in a relatively quiet location. The other question is that if she doesn’t make it should I reintroduce the female I removed? Mainly because I am not sure the remaining female will be big enough to handle the pups by herself.

Thanks for any help
Bruce