A treatment by day interaction was observed for Bursa of Fabricius weight relative to live body weight. The HVT control injection is represented by the gray shaded bar. The L. animalis injected probiotic treatment is represented by the white shaded bar. The E. faecium injected probiotic treatment is represented by the striped bar. The L. animlais + E. faecium combination injected probiotic treatment is represented by the dotted bar. Bursa weight relative to total body weight (%) is on the y-axis, and day of grow-out (days 0, 7, 14, and 21) is on the x-axis. The SEM and P value is located in the bottom right corner of the figure. Differences were considered significant at P ≤ 0.05, error bars represent the SEM, and N = 10 (10 pens/treatment; one bird randomly sampled from each pen on each sampling day). Significant differences are noted by alphabetical superscripts, where each change in a letter represents a significant difference among treatments. The superscripts for this figure include a—i.