Administration of a coccidiosis vaccine to day-old turkeys via the eye and development of immunity to Eimeria species.

Day-old turkeys poults were given a live coccidiosis vaccine via the eye at the hatchery, and all poults produced oocysts in their droppings 7 d later. No oocytes were present in droppings of unvaccinated controls. The weight gain of vaccinated poults challenged at 3 wk of age with a mixture of three species of Eimeria was lower than that of unchallenged poults, indicating that they were susceptible to infection. No significant difference in weight gain was found when poults were challenged at 6 wk, however, indicating that they had acquired immunity to the species used for challenge.