Possible Psycho Rat??? Opinions please!

[Batdad]

OK Question: When rats give birth is there a lot of after birth and blood? The reason I ask is that I have a colony of rats that killed off their offspring a little while ago but I attributed it to the fact that they were not settled in their new home and there was a really lot of activity going on around them at the time (building of their cabinet around them). This same colony just had another litter but it only has three pups and the day they were born there was a lot of blood in the bin. I mean two spots bigger than the size of an average man’s hand. The bedding that I am using is shredded paper and the blood seems to have been absorbed to a large degree, as well as the fact that they move the bedding around as required. You can still see the blood mixed in the bedding but not as obvious. The mom seems to be taking care of the three pups but I am suspicious that I may have a psycho rat in this colony that killed some of the litter off at birth. I know that three pups is a small litter but I think that may change with future litters as the colony becomes more comfortable in their new home. They have been in their rack now for a little over 2 weeks. I am feeding them cheap dog food, they lots of space according to the U of Michigan, and I check in on them once a day otherwise they have lots of privacy.

So it comes back to the seemingly large amount of blood, is this normal or am I looking at starting this colony over? Who needs a psycho rat in a breeding colony?

Thanks for any help or advice,
Bruce