Egg Production and Shell Quality in Temperature and Light Controlled Versus Uncontrolled Environment

THE factors that affect egg shell strength have been the subject of a considerable number of studies. Special attention has centered on the age of the bird (Morgan and Mitchell, 1938) and on environmental temperature (Warren and Schnepel, 1940; Wilhelm, 1940; Mueller, 1959, and others) two factors which are believed to be inversely related to shell strength. Since these studies did not include long-term observations on birds kept under constant moderate temperature conditions, the effect of environmental temperature could not be completely separated from that of age and seasonal physiological rhythms which have been shown to exist in the laying hen for several metabolic characteristics (Winchester, 1940). Therefore in the present study observations of seasonal and age effects were made on egg characteristics of birds kept in an environment where temperature and light were controlled, and on control birds kept in a natural environment with regard to temperature and light …