The objective of this study was to examine the effect of nicotinamide riboside (NR) on pectoralis major muscle (PM) development and growth...There were no treatment × location or main effects for all body morphometric measurements (P > 0.07), except chest width of chicks from eggs injected in the yolk were wider (P = 0.01) than chicks from eggs injected in the albumen... Injecting NR into the yolk sac of the developing embryo at day 10 of incubation increased pectoralis major development which was due to an increase in muscle density.