I have had chickens for a year and half. I have 100% emptied the coop 3 times. Typically I keep mixing and addi g. But then it will get to a point where it is kind of just stinky. And doesn't seem to be clean when I add fresh pine chips. That is the point when I clean it all out. Most of the poo is cleaned out of the coop on a regular basis tho. Because we have sand under the perches that we scoop with a kitty litter scooper. So there is a lot less in the litter on the floor. Our chickies free range. In warm times they only go in to at night and lay eggs. Durring the day they sleep in the sun or under the pines. Now that cold is here, they stay in more. So cleaning out actually happens more in the winter for me. Hope this helps 
