Me too, it also takes up floor space when it is probably crowded already. I think in general chickens do not like a two story coop. Also if the roosts are too high, heavy birds can get hurt making landings.
I think they would be much happier with a conventional coop. Rule of thumb 4-5 sq.feet per bird in the coop (excluding roosts and nest boxes) and 10 sq.feet per bird in the outdoor run.
Are your birds confined there all day, or do you let them run around a bigger area.? Chickens hate being crowded