At 25 days of incubation, eggs from Large White turkey hens in two field trials were injected with 87 micrograms of exogenous d-biotin per egg. Hatchability of fertile biotin-injected eggs was significantly higher than that of control (noninjected) eggs. Hatchability values of fertile eggs were 4 and 5% higher for exogenous d-biotin-injected eggs than for control eggs for December 1985 and May 1986 trials, respectively.