i've been successfully using peat moss as my sole bedding substrate in my coop and brooder for four years and have had no problems with excess dust or hens with respiratory issues. it is non-binding if eaten, fantastic for ground-dwelling birds (and dust-bathes up a treat), and needs to be replaced about four times per year in my flock of around 30 birds. i pick it weekly for organic debris from feeding and nest-box demolition, which fluffs it up nicely and keeps it drier. it has virtually no manure odor, very little ammonia odor in the depths of winter when the birds are inside a lot, and i really can't say enough good things about it. i'm always surprised at how few people use this as bedding. it's seriously the best thing ever.