Weight loss (12%) of turkey eggs in a commercial incubator by a weekly adjustment of relative humidity (RH) was compared in four independent trials with the industry standard of maintaining 58% RH. Trials 1 and 2 were conducted with eggs from one flock of recycled hens during their 14th and 20th week of lay, respectively. Trials 3 and 4 were conducted with first cycle hens during their 3rd and 10th week of lay, respectively. Hatch of eggs was significantly better when eggs were incubated to lose an optimum amount of weight. Hatch of fertile eggs was significantly improved (P less than .05) in all except Trial 2. Hatchability was best when loss of egg weight was not greater than 11.5% at 25 days of incubation.