1. Helerakis gallinarum recovered from chickens, and apparently having lived exclusively or predominantly in chickens for several years, thrived better in chickens than in turkeys, when several hundred embryonated eggs were given in a single feeding.
2. Use of a smaller inoculum reduced the difference in the worm's performance in its traditional host and the new host species.
3. Performance in both species of host was the same following the feeding of small numbers of eggs from worms grown 1 generation in turkeys.