The performance of broiler chickens as well as behavioural patterns (ingestive, comfort and agonistic) were investigated under the normal stress conditions throughout the experimental mentioned of this work. two hundred Hubbard day old chicks of both sexes were raised together up to two weeks of then were randomly divided into four equal groups (I, 11,111, and IV) each of 50 birds. Each group was housed in a separate room. The first group (I) was optimally accommodated and considered as the control, while the second group birds were exposed to 3000-3200 ppm of
tbon dioxide. The third group (III) was exposed 100-125 ppm of ammonia, last group (IV) was suposed to sprinking with 10 gm fine dust for 15 minutes daily. the obtained results showed that, the exposure of broiler chickens to some noxious stimuli stressors) throughout the rearing period has significantly reduced feed consumplion, weight  and consequently feed conversion compared to the control group. In addition, ingestive (feeding and drinking) and comfort (rest, sleep
and preening ) behaviours were influenced by stressors, in other side there was a significant increase in occurrence of agonistic behaviour (feather pecking and cannibalism) in the group exposed to stresses, this lead to increased
mortality percentage among those birds. So the environment inside the poultry house should be free from noxious stimuli (stressors) or with unavitable minimum level, to obtain good behavioural pattern, high performance and efficiency from the birds.