if you put a roof on top the roof needs to be like 100meters tall, exaggerating some but yeah, roof will bug them out if its not very tall.

Every 4 lox require 20 meters of space. If you don't have enough space they won't eat.

how far removed from the other lox are they? It's possible the devs increased the population limit range, or you have too many lox near your breeding pair though I can't say for sure.

Also, remember to account for the fact that they have the same model height requirements as trolls, if you put a roof over them it needs to be REAAAALLY high to ensure they still eat.