Ever seen a roof building rat?

[Batdad]

Don't know if this belongs here or not, but this is a weird one. I am in the process of building a rodent cabinet including an auto watering system. In the mean time the mice are on bottles and the rats have bowels. One of the rats, the male I think, has taken to wetting pieces of bedding, shredded paper, and stuffing it in the hardware cloth overhead, kind of like building a roof. Anyone ever seen this kind of thing before? They are kind of freaked I think because of all the activity going on around them. Although the other colony I have doesn’t seem stressed at all.

Bruce