I have 7 hens in a tractor coop that is about right for 4 (14 square feet in the coop part and another 24 sq. ft. in the run).
I use wood shavings in the coop and clean daily to remove the bigger bits. I fluff the shavings daily with a cat litter scoop, and when it gets icky, I'll change out the whole lot of shavings (or when it gets colder and I put the coop/run in a permanent place for winter). They have been in the coop since they were 4-5 weeks old and they are almost 14 weeks now, and I haven't changed out all the shavings yet. I mix shavings with DE, and put some fresh in each day to replace the removed dirty litter. It is about 3 inches deep (not really deep litter, but sort of). I clean the nest boxes daily, too. We have no smell except early mornings when one of the two windows has been closed during rainy nights. I'm working on a way to leave it open a bit with some sort of cover to keep the water out. They deserve a dry, clean, ventilated place to live.
My plan had been to rehome 2 or 3 of my girls before winter, but I'm going to try to work it out with them. They get free range time every day at least 3 hours, and the run part of the tractor gives them a bit more space that is sort of coop space. For winter when it isn't being moved daily, I'm going to put heavy plastic over most of the run wire (being sure that there is sufficient ventilation), and put 4 inches of sand in the run to give them more protected space on days too nasty to be out in the yard. They will still get free range time when the weather permits.
If they start feather picking or fighting, I'll have to rethink it. I just can't bear to part with any of them. Each one is such an individual. I have hope though. My husband told a friend (in my presence) that we needed to enlarge our housing for the chickens because they are too crowded. He says they are spoiled rotten.