I've been pouring over these forums for what might be the cause of this but my Urban Flock of 5 hens has been twitching their heads this summer since moving out into their coop. They're 19 weeks old and have been in their coop for a little over 2 months. During this time they developed this little habit of twitching their heads frequently. After digging around I came to the conclusion that it might be Gapeworm but looking at all the other symptoms that people mention for Gapeworm and all the other things I've found online they just don't match up to my flock. Symptoms: Twitching heads although not violently. Neck stretching and open mouth yawning although not very often. (I've always considered this crop adjustment or just yawning really.) Symptoms they DON'T have: No raspy breathing. No lethargic behavior. No runny eyes. No sneezing. No weight loss. No strange foamy poo. No signs of mites, lice, or other parasites and no issues with my dog who is out in the yard daily as well in this regard. Climate: I live in Northern Michigan and it has been a hot and humid summer but we're maintaining mid-80's right now with a decent amount of humidity this summer. They look and appear to be perfectly normal 19 week old hens. In fact one laid her 1st egg today and another appears to be close behind. Check out this video. This is not my chicken but happens to be exactly what they're doing. So before I go down a de-worming route on 19 week old hens can anyone chime in with what might be going on here. Thank you all on your comments and suggestions for my little girls.