A few years ago I kept 10 hens in a daily moving tractor around the yard because I HATE to clean a coop. Now I am reading so much about dust baths and controlling lice and mites. If they had lice/mites, I did not know it, not even the second laying year. I never heard any of the hens complain about not having a bath... Are dust baths necessary? Particularly if they are on fresh clean ground every day?