This study carried out on a flock of osimi sheep breeds belonging to the Faculty of Veterinary Medicine, Zagazig University, and as well as, a baladi sheep flocks, owned to a farmer at Zagazig center, in the period between the first of September, 2006 till the end of August 2007. This work included three experiments : I- First experiment : (Behaviour and Performance of sheep in relation to housing system) The obtained results in this experiment indicated the following : 1- The loose housed sheep spent lower time (min.) in eating, rumination and drinking compared with the tethered sheep (P  0.05). 2- The tethered sheep had more frequent urination and defecation than the loose housed one (P 0.05). 3- There was a significant difference (P  0.05) in standing, lying time between loose housed sheep and the tethered one. As the tethered sheep spent more time in this activities. 4- Mean live body weightgain was greater in the tethered sheep compared with the loose housed one (P  0.05). II- Second experiment : (Effect of feeding regime on behaviour and performance of sheep) The results of this experiment were explained the following: 1- The providing of sheep with its daily ration divided into small frequent amounts at different time, resulted in a significant increase in its eating, drinking and rumination time. 2- There was a significant difference (P 0.05) in frequencies of defecation and urination between fixed feeding group and Irregular feeding one, as the irregular feeding group had more frequencies than the control one. 3- The sheep in fixed feeding group spent more significant time min.(P 0.05) in standing and lying than the irregular feeding sheep. 4- There was a significant difference (P 0.05) in live body weightgain between fixed feeding group (28.68  0.46 kg/8w.) and irregular feeding one (38.70  0.34 kg/8w.). As the later group achieved more weightgain. 5- The mean level of serum cortisol in the irregular feeding time (0.95  0.52 mg/dl) was not significantly higher than the fixed feeding one (0.720.22 mg/dl). III- Third experiment : Effect of stress factor(isolation) on behaviour and performance of sheep The obtained results in this experiment were included the following: 1- The isolated sheep spent lower significant time (min.) in eating, rumination and drinking compared with the non isolated one (P  0.05). 2- There was a significant difference (P  0.05) in frequencies of defecation and urination between non isolated sheep and the isolated sheep had more frequencies of that activities. 3-The isolated sheep spent more significant time min. (P  0.05) in standing and lying than the non isolated one. 4- Mean live body weightgain was more significant in the non isolated sheep compared with the isolated one (P  0.05). 5- The mean level of serum cortisol in isolated sheep group was significantly higher than that of non isolated one.