I'm building my first set of perches for 4 hens. As you can see below there are 2 perches, each about 4' wide. They are 9" apart from each other and the back one is just 6" from the wall. I'm wondering if this is enough clearance all the way around (will chicken bums take up more than that 6" I left to the wall on the top perch?) I assume this will work but wanted to get some opinions...thanks!