The basic vitamin requirements of the bird must be more clearly established before the true effects of temperature can accurately be measured. Although the literature reveals progress, the knowledge gained (as in many other fields of scientific investigation) is spotty, contradictory, vague, and intriguing, providing a basis for further planned comprehensive investigation. A review of literature leads to some general conclusions on the effects of temperature on vitamin requirements. 1) Feed consumption regulates vitamin intake, and feed consumption is closely moderated by environmental temperature, both high or low and to a varied extent. 2) Factors involved in management, growth, egg production, light, etc. are very influential interactions. 3) High environmental temperature and subsequent heat stress will result in altered availability and utilization of specific nutrients. 4) There are factors regulating nutrient intake that relate to utilization, such as energy-protein ratio, management, age of bird, and genetic composition of the bird. 5) Care and treatment of feed, age, storage conditions, pelleting, and characteristics of the ingredients are important influences.