So we've been raseing chickens for the last four years with out a problem one. But this year so far we've lost three all with the same symptoms. The stop walking on their feet. Won't eat or drink. Not active. We have lost 2 red sex links and a Cochin so far then tonight I find one of our 4 month old leghorns with a large bump on her head with a crusty cap. All were wormed 4 days ago. The other three died about a month apart from each other.