Experimental approaches to stress diagnostics in poultry (review)

Special data concerning stresses in poultry and their diagnostics in the laboratories and at the commercial farms are summarized. To estimate the adaptation mechanisms and individual stress resistance in chickens, different procedures have been reported till now. But the methods in which the blood biochemical stress markers must be analyzed are hard to use at commercial farms so far as special equipment and qualified personnel are required. Besides, the biochemical data from these tests are not reliable and accurate. Calculation of the blood heterophyls to lymphocytes ratio is considered as easier and more informative, and the feathering is referred as the highly valuable indicator of chronic stresses, especially if combined with the stress hormones contents in blood and the time of tonic immobility of chickens. Nevertheless, to evaluate these parameters, a chicken should be subject to the manipulations which are the stressors itself, while only the minimal impact ensures a reliable stress indication. Because of that we improved the method which allows diagnosing stress in parent flocks of the meat chickens by corticosterone test in excrements. The method can be used to control anti-stress therapy, to optimize the chicken flock size and crowded conditions, and to analyze the impact of applied technologies and veterinary treatments in poultry.