I suspected worms for a little while so I used a pellet dewormer I found at TS. I noticed a small difference in the chickens, but at the same time I'm dealing with poultry lice in about half of my flock AND three hens who have bumblefoot. I partially blame myself for not inspecting them close enough... just last night I went to spray everyone with a solution for the lice, when I noticed a long, white string hanging from my 4 month old chick! I knew it was worms after I noticed the eggs in the chicken poop. I've identified them as tapeworms, so although I would prefer a natural method, I know I need medication for tapeworms. So, I'm treating all 20 chickens just in case.