During the past year about 50 domestic hens from a farm at Wheathampstead, Herts, have been sent to this laboratory for postmortem examination. The birds came in singly at first. Later as the helminthic fauna seemed likely to prove interesting, they were kindly sent in groups of three. When a diseased bird died, a thin one and an apparently healthy one were slaughtered so as to effect a control. The hens had been bought as adults from a number of local farmers and were kept outside on free range. They belonged to the breeds Ancona, Light Sussex, Rhode Island Red or were a cross between R.I.R. and Light Sussex. All the birds seemed to be equally affected.