IN a book I have on chickens called Storeys guide to raising chickens, it says that a worm called a gape worm that invades the windpipe. Signs are: coughing gasping and head shaking (in an attempt to dislodge the worm) my chickens are all shaking their heads about ever fifteen seconds. No coughing or gaspins, but I am still worried. What do you think it is???