IS THERE A POSITIVE SIDE TO STRESS

Although it is generally assumed that stress is detrimental to the wel l-being of poultry, there are positive aspects which are often overloo ked. In the context of evolution, stressors such as infectious agents, climatic extremes, and domestication processes play important roles i n inter-population and intra-population genetic variability. Pathologi cal, immunological and behavioural studies in both avian and mammalian species indicate that too much or too little stress is undesirable, a nd that a certain degree of stress is essential for maintaining normal biological functions. Prior stressful experiences, particularly durin g the neonatal stage, may have long-term benefits in helping an indivi dual to cope with subsequent stressors. Reliability of stress indicato rs and their variability at both population and individual levels is a major factor in attempting to quantify 'optimum stress'.