This has to be one of the most thoughtfully written posts I've seen in a very long time.Just popping in to toss my $0.02 in. I've been keeping a flock under the same conditions for nearly 5 years now. Not as long as some folks, but it matters still I think that my birds have lived this way for that long. Also, I'm feeling a little aggressive today, so my apologies if this seems harsh.
I have never used a medical dewormer. I don't have parasite loads or problems. I have chickens in a small coop and pen in suburbia (about 750sqft with 10-14 LF chickens at any given time, meaning each bird has about an 8'x8' area). You do not need to worm constantly, even in suburbia. If you need to worm constantly, there's probably something seriously wrong with your management. That could be that you have too many birds for your area (Which DOES mean if your area is too small, you could have too many birds with just 2-3 bantams. There's a real possibility that owning chickens is not appropriate for your situation, like sticking a st bernard in a one bedroom apartment. There's a point where it's not enough space to keep healthy birds.), or you do not cull weak birds, or you do not use soil management or you need something more work intensive (like regular cleanings) or something. So here's how I manage parasites and I think that most of this is already in the thread but I just wanna say I agree with it.
1. Soil management. I lay down fresh woodchips in my chicken pen 1' deep every year or two. The fresh woodchips last longer and break down slower. The chickens dig in the woodchips, mixing them with their own fecal matter and they compost down into harmless dirt. There's 5 years of chicken poop in my chicken pen and you would never, ever, know it. I never take anything out or clean it, I just add more in. This creates a really violent environment for pathogens and parasites and they just can't survive in it. Everything has a natural predator, even tapeworms, and the deep litter is a motherload of things that feed on things that are bad for my birds. Deep litter is great.
2. Culling. I never really get around to culling my own birds. The local hawks do too good of a job of it for me.But I agree strongly with culling. A sick bird is a huge risk, kind of like how if you catch the flu it puts you at a greater risk for pneumonia. Yes, some of these birds are beloved pets but those pets have wide-reaching consequences. A simple example, in 2003 an Exotic Newcastle outbreak that resulted in 3 million chickens destroyed started in backyard poultry flocks in California and spread to four states. I'm not saying that your birds are carrying a nationally-threatening virus, but if you think that the worms you chickens carry won't be able to spread to the chickens 5 blocks away, or that little runny nose doesn't mean something bigger could be going on internally, you're wrong. And your negligence could effect more than just your own flock. Bird-borne pathogens and parasites spread fast, kill effectively, jump species easily, are hard to control and threaten our national food supply. Even dogs get put down if they carry a dangerous contagion. Responsible euthanasia is part of responsible chicken keeping. If you own chickens, you need to own that, as difficult as that is.
3. Diet management. If you feed a low quality diet, your birds will have low quality health and be more prone to all sorts of diseases and parasites. This can also be done effectively in small spaces. Fodder, fermented feed, probiotics, vegetable scraps, worm bins and other methods can be used in small confinement spaces to encourage a healthy, natural, diet. I put extra effort into deworming in the fall, not on purpose but by coincidence. Early November, right as my birds are going into molt, I try to do my errands on trash days. Anytime I can, I stop and pick up old jack o lanterns and pumpkins and other squashes from peoples tree lawns. Sometimes they have seeds, sometimes not, and I get my fall squash coming in so they get those seeds too when I eat those. Sometimes they're a little moldy, but I don't worry too much about that. This is the closest thing to a natural dewormer I use. It's a fall bounty that dang near any suburbanite can get their hands on for free and it's great. Sometimes if I feel like my flock has had a rough time I might soup this up with cayenne or garlic in their feed to try to give them a little extra boost.
4. Other environmental management. Making sure your birds are healthy stops parasites from taking over. Obviously, they're there the whole time but healthy birds don't worry about it. So in addition to diet and culling and deep litter, I also make sure all the other little details are in place. A bird with external parasites will be likely to have an outbreak of internal parasites. A bird that's having trouble with eating won't have a strong immune system. A bird with no exercise or poor mental stimulation will be less robust. So I try to make sure my birds have what they need, even in a small space. A dust bath filled with sand, DE and wood ashes gives a natural source of grit and minerals and external parasite removal. A cinder block gives birds somewhere to wear down their beak. Swings and branches and boxes and perches and tunnels give the birds things to stimulate mind and body (and conveniently so too does the deep litter).
An interesting note about this. Something that really improves the health of animals in captivity is mental health. Zoos found this out and they found that one of the biggest contributing factors to mental health was not how much space the animals had but rather if they could see the entirety of their enclosure. So they started adding alcoves and passages and visual blocks to their envrionments and it really improved the animal's physical and mental wellbeing. Animals in thoughtfully designed enclosures got sick less often than ones in more open enclosures. I guess seeing your whole entire world at once is pretty depressing.
And that's it. That's all I do. And it works, even in small suburban spaces. I never see worms, and I don't worm my chickens. They don't even really get the free range like some birds on here. And it's not scientific evidence, but... You're on a chicken forum not a scientific journal.
