Hi My 5 1/2 month old Delaware hens won't roost on their perch at night, they sleep on the floor of their Rubbermaid shed. The roosting perch has been installed for about 10 days and is about 28 inches off the floor. Should I lower it? Its a single long perch running the length of the small shed. Should I try a ladder style one or maybe a couple going across the width? I worry that with the cold air coming in the door-hole they ought to be up off the floor. Any ideas? Thank you!