I have four 2 1/2 month old chickens and two 3 1/2 mo. old guineas. They are in a 11'x5' tractor and have been since 1 mo. old. I have a roost across the width of it only about a foot off the ground (I've lowered it over time) and I've never seen ANY of them on it!! Not enen the guineas and I thought they would roost anywhere. My kids have put them on it, so they know it's there. What's up?? Should I be worried?