So we just culled our first chicken for food. After cutting the head off, my wife observed a white roundish worm in the neck. It apparently crawled back into the neck and we never saw it again. I inspected the stomach, crop, intestines, and never found another one. Is this something I should be concerned about? Also, if I do worm, is there ANYTHING that can be used that will not require a 28 day withdrawal period? My birds all seem healthy, and lay great. Not sure if I really have a problem here...the culled bird was a 6 month old mixed roo.