Stress susceptibility of chickens is a major
problem in the modern intensive poultry industry.
Birds are often subjected to stressors such as
fasting, transport and exposure to high or low
environmental temperature. During stress the
endocrine system is markedly affected. The
hypothalamus—pituitary—adrenal axis and thyroid
glands are seriously affected by stress (Siegel,
1980). As a result of stress, feed consumption,
growth rate, feed efficiency, eggshell, fertility and
chick quality decline