I have four, one-year-old hens that have been laying in milk crates (on their sides) on top of concrete blocks (also on their sides). I also have five hens that just started laying. I built two additional boxes out of crates and secured them to the top of the current nesting boxes. I have golf balls in all boxes and perches on both levels so the hens can get up to the boxes. None of the hens seem to have noticed the top boxes. Maybe they are too high? Any tips for getting hens to lay in top row nesting boxes?