Quote: Funnily enough I never use chemicals and have never had a problem with lice or mites, even when heavily overstocked for a long time. Neither do I vaccinate or give medicated crumble or feeds or use man made antibiotics. Don't believe chemicals are the only way, they're a way that must be phased out to move forwards into a future that leaves a functioning world for future generations. I don't have lice or worm problems in the first place because I always feed raw garlic and kelp. If I bring in a new bird from outside breeders with for instance scaly mites or heavy lice, I treat that bird through diet, and for messed up scales I use Stockholm Tar (multiply boiled pine sap) or other natural things like neem. I don't bother treating the perches or the other birds. They're fine because they're abhorrent to parasites due to their health and their garlic-rich diet. I never wash or dust for lice. It's all quite easy once you start with garlic and kelp, and just maintain that. I do give other herbs too, like sage, rosemary etc, which are also vermin-repelling.
Quote: Have you heard of the deep litter composting method? I highly recommend it. It was developed by some American scientist who studied it for decades and proved its worth. It shows that the cleaner you keep the environment, the more birds you lose. Good healthy deep litter only needs occasional liming and sometimes charcoal, and clean out excess once a year or so, for your garden, but never fully clean. It isn't bone dry, but it's full of healthy microbes, fungi etc which act in such a way as to immunize your poultry and kill diseases in the litter. It basically makes a cultivating layer of healthy organisms that keep it sweet, clean, and healthy, unlike a regularly cleaned coop floor which sours up quickly and tends to stink. Once you get a healthy litter going it takes care of itself, basically.
@the threadstarter saying their chickens have black spots in their crest and wattles... That sounds like something other than lice, to me. I've seen chickens get mold on their crests and wattles, when not kept on regular garlic. Once you raise a bird on medicated feeds and vaccinate it, though, it can be pretty impossible to get it up to the standard of health comparable to a bird raised naturally; it took me a couple of natural generations before the chicks started to show all the benefits that had been put into their parents. I'm quite a newbie but I have dealt with chemicalized and non-chemicalized birds in sickness and in health and I'll never bother with one of them again... Guess which.

You just can't restore full health once it's been artificially destroyed. We aren't adapted to cope with the chemicals we're using, and we confuse surviving with thriving.