I had a hen with Gape worm and I tried everything. She had it for more than six months. I gave her drops of Ivermec and them sryinges full, enough for a few sheep, I gave her horse wormer, again, first a little and when I saw no change I gave her more, enough for a small horse. She just lost weight and faithfully followed me out to the garden to eat worms. It was the only thing she wantwed to eat. I guess she needed the protein. I tried to feed her with a syringe with vitamins to help get weight back on but I ended up causing herr to choke and she died. She gasped all the time. It was so hard. I don't think that I could have "culled" her but I understand why people do. All I could think of was the worns were using her as a host and now they would be depositing their eggs into the soil for my other chickens to eat. I haven't had any others get it. It was awful.