Heart Rate Studies with Scaleless Chickens

Abstract

INTRODUCTIONA NUMBER of single gene mutations in the chicken result in abnormal plumage; reviewed by Abbott (1967). Birds with deficient insulation, are particularly susceptible to subnormal environmental temperatures. By far the most severe feather tract deficiency occurs in the autosomal recessive, scaleless (Abbott and Asmundson, 1957). Selection first for resistance to cold stress and then for increased and decreased numbers of feathers resulted in two lines well separated in degree of feathering (Abbott and Asmundson, 1962; Abbott, 1965). Many scaleless birds in the high feather line (ScHi) are now completely covered with plumage; albeit this remains primarily juvenile in form. Birds from the low feather line (ScLo) are virtually naked. These provide an excellent tool for studies of the many effects of prolonged hypothermic stress.In this study, heart rate and heart size of the two selected scaleless lines were compared with three different sources of normal chickens; Single Comb…