Figure 1. Best-fit trend lines of total heat production using data collected from several different studies (both toms and hens) for a temperature range of 59°F to 86°F for genetic lines from two periods.
Graph showing the relationship between turkey weight (in pounds) and total heat produced (in BTU/bird) for genetic lines: 1974-1977 and 1992-1998

Source: Chepete and Xin, 2002