I thought it was just the cord at first. I have never seen mine give birth, only heard them walking by. I also only had one colony cannibalize and could not figure it out until I saw a female whooping the only male (his neck was bloody) in there when he was trying to take a baby...he exited the colony right away.
Veeryy nice rat colony, they kind of look like mice pinkies at first I also saw the collection video woahhhhhhhh huge fan of pewters, Mojaves, and bumblebees , yours are good quality