Effect of poultry red mite load at the time of scoring on plumage condition (A) and skin injuries (B) during the laying period.

PRM–poultry red mite; LM–laying month. Quartiles were calculated for the mean mite mass (of 10 mite traps) per flock and monitoring date using data from the entire study period: Flocks were classified for each monitoring date as follows: PRM / (low mite load, i.e. flocks with mean mite mass <1. quartile), PRM + (moderate mite load, i.e. flocks with mite mass between 1.- 3. quartile), and PRM ++ (high mite load, i.e. flocks with mite mass >3. quartile). The percentage shown per plumage score corresponds to the arithmetic mean of the three assessed plumage regions (dorsal neck, back, and belly plumage).