The goal of this study was to provide a global assessment of the host's response to M. gallisepticum over a 7-day time course Overall design: Differential gene expression was assessed between Rlow infected and Hayflick's only 'control chickens' on days 1, 3, 5, and 7 (5 infected per day, 4 controls on day 1, 5 controls per days 3, 5, and 7), 39 total chickens assessed.