I have five girls...the three oldest should be laying any day now. The two newest girls are about 3 weeks younger. The coop is a fairly new addition, and the girls have been sleeping in it about a month...the two Orpington's (the two youngest) won't sleep on the roosting bar...they like the floor. Up until yesterday, when one of them decided to sleep in the nesting box. I have an idea she thinks we put them in just for her! The box is about 18" off the the floor. Any suggestions?