We also use Sevin dust. We also use a pour-on cattle dewormer (rotating Eprinex and Ivomec) that will get rid of both internal and external parasites twice a year.
If your chicken was sick, would you treat it with antibiotics or antifungals, or just cull it or let it die? Those aren't "natural" either. Many natural remedies will help to keep a parasite load down, but won't actually treat an ongoing infestation.
Well anitbiotics are natural. They come come from fungi and other bacterium. It's the way they defend themselves against other bacteria.
Using those poisons actually doesn't treat the problem. Check out the research concerning wood ash, diatomacious earth and peat moss. It actually does solve the mite problem and other external parasites. It might be termed an enabler as it enables chickens to clean themselves more fully.
When you give them those dewormers that weren't made for poultry do you eat the eggs being produced?
If a chicken is sick it would depend on the illness and I wouldn't let it die I would end the suffering quickly. I am not claiming to anthropomorphize my animals. I love them and treat them with the utmost respect and humane care. But I breed my birds so that they can deal with the natural stresses of their environment. I wish I could believe in quick fixes bought in a store.
It once was said that arsenic and mercury could cure many ills but it didn't make it right then and I'd bet none of you would use them now.
I do not think I am better than you. I am not engaged in a competition. The result of life is death. The price for a breath of air is that one breath will be your last and so it is with all animals.
There are some medicines out there that might be useful. But thankfully so far I have not had a need for any of them. DE has worked great. My goats get it as well and they have great color.
My only point is that there's a balance(and it never sits still in nature), and many times illness, parasite infestations etc. come about because somewhere there is an imbalance. Weather conditions can lead to a perfect environment for some organisms and they take off. There may be a time when it is appropriate to use a poison. But if you do things right that should be a very rare time indeed.
Cheers and may you enjoy your flock.