An extensive literature review and comparative analysis of heat and moisture production of various poultry types and their housing systems are presented. From each published article, the data extracted included breed, body mass (M), and age of the birds; temperature, RH, and photoperiod maintained during the study; measured values of latent heat (LH), sensible heat (SH) and total heat (TH) production; the type of study used (direct vs indirect calorimetric studies); feeding regimen (ad-libitum vs restricted); number of birds used; duration of the study and the type of waterers used. LH, SH and TH were explicitly indicated in some articles while in others, regression equations were published. Specific total heat production (THP, W/kg) was observed to have increased over the years in all poultry types. Specifically, THP increased by about 21 to 44% over a 14-year period (1968 to 1982) for broilers weighing 0.1 to 1.6 kg and by 15 to 22% for broilers at 1.4 to 1.6 kg over a 32 year period (1968 to 2000). Only one study was found for pullets and data were thus insufficient to draw any conclusions about the trend of THP. Data for pullets & layers between 7 and 33 wk old at thermoneutral environment are not available. Tom turkeys weighing 0.4 to 1.0 kg experienced an increase in THP of 36 to 63% over a 24-year period (1974 to 1998). Data for heavier turkeys were insufficient to make reasonable comparisons in the trend of THP. The metabolic rate equations derived from the literature data were in good agreement with the standard metabolic rate HP (W/bird)= a M b, where b = 0.66 to 0.75. Specifically, it was 10.60 M 0.74(1982 to 2000) and 8.31 M 0.71(1968) for broilers; 6.20 M 0.71for pullets and layers; and 9.83 M 0.74 (1992 to 1998) and 7.74 M 0.48(1974 to 1977) for turkeys.