A comparison of methods for exposing chickens to Coccidiosis in floor-pen trials

Three floor-pen trials were conducted for the purpose of evaluating 4 methods of exposing broiler chickens to coccidiosis. The methods were compared on the basis of their effect on weight, feed efficiency, histological lesions, and mortality. In each of the individual trials, birds exposed to coccidiosis via the feed had significantly (P is less than 0.5) higher incidence of light to severe histological lesions that those exposed via "seeder birds" or contaminated litter. On the basis of pooled data from the three trials, birds exposed via the feed had lower feed efficiency, higher mortality, and significantly (P is less than 0.5) lower weight at 8 weeks than those exposed via the other techniques. However, the feed method of exposure resulted in a significantly higher variability (P is less than 0.1) in mortality among pens. For uniformity of infection, it was concluded that the most satisfactory method of exposing birds to coccidiosis in floor pen trials was to spread laboratory sportulated oocysts over the litter.