If your coop is not moveable, the first thing you need to do is stop using shavings, period. Line the bottom of the coop with hay, not straw. The roos will eat the hay, scratch thru the hay and keep the poop down on the bottom where it will mix with the dirt, instead of just laying on the top like it does with shavings. You also need plenty of ventilation to help keep down the ammonium smell. Your birds will stay much cleaner also.