And that is 4 sqft per chicken.Chickens need 4 square feet of room in the coop, and one linear foot of roost space per bird, even though they may all cram into one space.
Your birds are roosting on top of the coop because it is too small and the roosts are too low. They feel safe up high. Is there any way to enclose the "run" part of the coop in order to expand the coop, and add suitable ventilation, which is seriously lacking in prefabs?