i have 25 hens in a coop. i have an old ladder up for them to roost, plus some shelves which they seem to like at night. i have also have 12 nesting boxes. its about 2 feet off the ground and i have some planks with footing leading up to them. i keep them lined with sawdust and hay. however, the chickens don't seem to care at all. they are about 4 months old -- and they aren't laying yet. is this normal, or should i rethink my design? the nesting boxes are about a foot wide and a foot and a half deep.