Statistical analyses of chicken intestinal lesion scores in battery cage studies of anti-coccidial drugs.

•Coccidial lesion scores were analyzed under the generalized linear mixed model.•The normality assumption for the model random effect was reasonably satisfied.•Estimates of model random effects agreed with the study setup.•Results of efficacy testing were in concordance with the linear mixed model approach.•A 10-fold increase in the odds of success represents a clinically relevant efficacy.