Relative abundances (%): bacterial phyla (a) and most abundant bacterial genera (relative abundance > 0.5%) (b) in feces at 16 and 29 dph in low- and high-RFI broiler chickens receiving either a FMT or a CT. *, P ≤ 0.05 (effect of time point); **, P ≤ 0.10 (trend for time point effect); †, P ≤ 0.10 (trend for RFI rank effect); ††, P ≤ 0.10 (trend for FMT effect). Low-RFI FMT females, n = 8/time point; low-RFI FMT males, n = 7/time point; high-RFI FMT females, n = 7/time point; high-RFI FMT males, n = 6/time point; low-RFI CT females, n = 7/time point; low-RFI CT males, n = 7/time point; high-RFI CT females, n = 7/time point; high-RFI CT males, n = 7/time point. Uncl., unclassified.