Ethological and Physiological Indices for Well-being in Broilers under Different Systems of Management

1 Institute of Animal Science, BG-2232 Kostinbrod, Bulgaria
2 Trakia University, Medical Faculty, BG-6000 Stara Zagora, Bulgaria


POPOVA-RALCHEVA, S., V. HADJIILIEV, D. GUDEV, A. ALEXANDROV and V. SREDKOVA, 2002. Ethological and physiological indices for well-being in broilers, under different systems of management. Bulg. J. Agric. Sci., 8: 635–639

The objectivity of chicken well-being assessment depends to a great extent on the correct choice of the corresponding indices. In the present study we tried to assess the reliability of same indices of stress when the system of management engender social conflicts.
Broilers (n = 2700) were allocated into 3 groups: I group (male broilers), II group (female broilers) and III group (male + female broilers) – raised under similar conditions.
Aggressiveness at 4, 6, 7 and 8 weeks of age, plasma levels of corticosterone, glucose, cholesterol and adrenal and bursal weights at 6, 7 and 8 weeks of age were assessed for their reliability as stress indicators.
It was established that the ethological parameter aggressiveness correlated positively with the most reliable biochemical indicators and could be used separately as a simple and easy way for rough evaluation of chicken well-being in practice. In this study the adrenal weight of broilers is more reliable index for broilers well-being, than corticosterone and cholesterol level. Unisexually raised male broilers were in a better position, concerning their well-being, than unisexually raised females or mix-raised broilers.

Key words: well-being, aggressiveness, corticosterone, cholesterol
Abbreviations: HPA– hypothalamic-pituitary-adrenal, ACTH-adrenocorticotropin