Behavioral changes and feathering score in heat stressed broiler chickens fed diets containing different levels of propolis

This experiment was conducted to evaluate the effects of dietary supplementation of green Brazilian propolis on behavioral patterns and feather condition of heat stressed broiler chickens. Five hundred and four (504) male Ross 708 broiler chicks at 15-day old were randomly allotted to six dietary treatments containing 0 (control), 100, 250, 500, 1000 and 3000 mg kg−1 propolis, respectively. Each treatment consisted of four replicates of 21 birds each. Heat stress at 32 °C was applied daily from 08:00 am to 17:00 pm from day 15-42. Twelve birds per treatment were randomly taken and marked with livestock color for behavioral observation. Treatment effects on behavioral patterns were recorded using direct observation instantaneous scan sampling technique. At the end of the experiment (42 days of age) the three birds used for behavioral observation were feather scored (from 1 to 5); while all birds (504) were individually scanned for primary feather abnormalities. The results indicated that the effects of using propolis as a feed additive for broilers reduced heat stress behavior, especially dietary treatment with 250 or 3000 mg kg−1 propolis, by increasing bird walking activities and reducing panting behaviors (P < 0.05, respectively). Moreover, 250 mg kg−1 propolis (P < 0.05) increased standing behavior also. Walking activities was also increased in the birds fed with 100 mg kg−1 propolis (P < 0.05). There were no significant (P > 0.05) treatment effects on sitting, preening, feeding, drinking, wing elevations and feather pecking activities. Propolis at current doses did not significantly (P > 0.05) improve feather scoring, but reduced (P = 0.048) abnormal shape of primary feathers. The current results support that propolis treatment may be considered as a protective management practice in broiler chickens to alleviate the negative effects of heat stress, but further investigations may requested to determine the best type, dose, time and duration of its administration.