For 14 cats you do not have nearly enough litter boxes! You need 15, or 10 and clean multiple times per day.

Cats do not like having many of them living in close quarters. I am at my lmit here with 8 cats in rooms. Have to keep the cellar door open a lot sothey can go down there. So it may be territorial but if it is, then they are not going to stop. Spreading them out to the cottage was a good start.

Please add some boxes for them!