my chickens have been acting wierd but fine for months. it started in the late fall and has recently gotten worse. They shake thier heads and try to gag something up almost like they are choking, no discharge, no visible worms in feces. Not actually coughing anything up, nothing. they eat, and drink just fine, run around like normal birds, fight a bit here and there over treats but nothing other than the gagging and head shaking. I have read to treat this with ivermectin if it is gape worm, but i don;t know how much and if it is topically or orally. someone had said i could tell by looking in thier mouths but the ones that have been doing it longer are 14 lb. Roo Wyandottes that try to eat me every morning as it is. I'm supposed to grab them, open thier mouth and look down there? Ha! anyway, I worry about them even the Attack Roos. I love every last one of them and my kids all claim them. I love to see them eat worms and spiders and such, so I am going to start worm farming to make sure they get treats that won't cause a problem. Thanks for all the help in advance.