Quote: I would spray the inside of the coop with sevin or frontline spray and hang several strips. You put a couple on the nest boxes and by the door. You can sprinkle some food quality diatomaceous earth when you clean the coop. Ivermectin seasonally is a good idea but it might not be necessary that often. I would check the chickens seasonally to see it they need to be treated. Ivermectin treats worms too, so you can take some manure in to a vet for a float test and check the chickens for lice and mites with each season change.
I read somewhere that all free range chickens get worms, lice and mites, so like dogs and cats, all chickens should be treated for worms, lice and mites at least when they are young(three months or before laying starts). Lot's of things that I have read say making sure your chickens don't have parasites is the best thing you can do for them health wise. I have even seen it in a list of things you are supposed to do before collecting eggs for hatching.
Wild birds bring in the parasites to your flock, so bio security does not really stop it. Fowl pox is carried from flock to flock via mosquitoes. I don't know if Fowl Pox is a problem in Redding.
This is all prevention. You could be fine not doing any of this, but it really is not that much work. Ivermectin is a couple of ccs in a gallon of water for two days and then repeat 10 to 14 days later. You can still eat the eggs too. It is a lot of work getting rid of parasites and one type of mite can kill a chicken.
Ron