SUMMARY This study carried out on laying hens (Bovans strain) at the Research Farm, Faculty of Veterinary Medicine, Zagazig University in the period between the first of November (2009) till end of October (2010). This work included three experiments to detect the effect of housing system, stocking density and light duration on the behaviour and performance of laying hens. I-First experiment:- Behavioural, productive and physiological responses of laying hens in relation to housing systems. In this experiment 100 laying hens 19 weeks aged under two housing systems (battery system and floor housing system). The obtained results of this experiment could be summarized the followings: 1- There was no significantly difference (p < 0.05)in the feeding behaviour (time and frequency) of laying hens housed in battery or floor systems, while drinking frequency significantly higher in battery system (15.7 ± 1.1bout) than floor system (10.5±0.9 bout). 2- The standing time and sitting frequency were significantly higher in battery housed hens than those housed in the floor system as well as, standing frequency and sitting time were higher in battery system but the observed difference did not reach the significance level. 3- On contrary, the walking behaviour was higher in hens housed in floor system compared to those in the battery system. 4-The comfort behaviour including feather preening, dustbathing or sham dustbathing and other comfort behaviour were not significantly differ between two housing systems. 5-The hens housed in battery spent more time in aggression compared with floor system although the frequency in two systems not differed. 6- The time of abnormal behaviour was higher in floor system (76.3 ± 39.3sec) than battery system (39.6 ± 6.9 sec) but not significant, while its frequency was significantly (P≤0.05) higher in battery system (4.1 ± 0.6) than floor one (1.8 ± 0.5). 7- Egg production and its weight were higher in battery housed hens than other in floor system but the recorded difference did not reach the significance level. 8- Cortisol level did not differ between two managerial systems. 9-The mortality percentage was 6 % in floor system while it was not recorded in battery system. II-Second experiment:- Behaviour and Performance of laying hens in relation to stocking density. a) Battery system: studying the effect of different stocking density (2, 3 and 4 hens per cage) on behaviour and performance of laying hens. The obtained results were as the followings: 1-The feeding behaviour (time and frequency) was significantly (P<0.05) affected by stocking density, where three birds per cage had the lowest feeding behaviour (466.67±24.48 b sec and 23.75±0.95 b bout) than other treatments. Moreover, drinking frequency was significantly increased with increase the stocking density. 2-Standing time was significantly higher at three birds per cage (774.75±17.35a sec) compared with other groups. 3- The other comfort behaviour (head shaking, wing flapping, leg/ wing stretch, body shaking and tail shaking) was significantly higher at three birds per cage (2.65±0.31a bout). 4- The hens housed in three birds /cage had the lowest aggression behaviour than others housed in two or four birds per cage but the recorded difference did not reach the significance level. 5- The time of abnormal behaviour was significantly higher for the hens housed at greatest floor space allowance than other housed in lower floor space. 6- The hens housed at four birds /cage had the greatest egg production than others in other groups but egg weight was not significantly differed between three treatments. 7- Body weight of laying hens was significantly increased with increasing the space allowance for hen per cage. 8- The stocking density had significant effect on Cortisol level of laying hens. Two hens per cage had lower Cortisol level (1.39±0.08 b ng/dl) than hens housed at three or four per cage and group of four hens per cage had one mortality case. While, it had no significant effect on antibody titer of laying hens in first and second response 9- The hens housed two per cage had significant better signs of health. B) Floor system: studying behaviour and performance in relation to stocking density (7, 9 and 12 hens /m2). The obtained results from this experiment summarized the followings: 1- Feeding behaviour of laying hens was the highest in 9hens/ m2group and the lowest in 7hens/ m2group .On the contrary, the drinking frequency was significantly lower in 9hens/ m2group and higher in 7hens/ m2group. 2-Stocking density significantly affect on their physical activity. Standing time was increased with reduction of the space allowance while, walking behaviour was increased with lowering stocking density and sitting behaviour was the lowest in 9hens/ m2group. 3-There was significance difference in feather preening of laying hens in floor system where 9 hens / m2 had significant lower frequency than other stocking densities. While, other comfort behaviour was not affected by stocking density. 4- Perching behaviour was significantly higher in 9 birds/m2. Also, hens spent significant lower time (26.83±4.86b sec) in foraging behaviour in high stocking density (12birds/m2). 5- Aggression behaviour was significantly decreased with increase the stocking density. However, abnormal behaviour was significantly lower in high stocking density. 6- Egg production was significantly greater with increasing space allowance per hens. Also, egg weight was increased with more space allowance per hens but did not reach the significance level. 7- The food consumption was not significantly influenced by stocking density. 8- The level of Cortisol of laying hens was significantly higher (1.89±0.04a ng/dl) in high stocking density, while mortality rate was increased with increasing stocking density. 9- The hens housed at lowest stocking density had significant better signs of health. 10- Antibody titer of laying hens in first and second response did not affected by decreasing floor space. III-Third experiment:- Behaviour and Performance of laying hens in relation to light duration. A- Battery system: The obtained results from this experiment explained the followings: 1- Feeding behaviour was not significantly higher in control group (17 hrs photoperiod); also drinking frequency was significantly decreased with increasing light duration. 2- Standing behaviour was lower in lower photoperiod, however sitting behaviour was not significantly differed under different photoperiod while, walking behaviour was significantly lower in high photoperiod. 3- Control group had higher comfort behaviour however; it had non significant lower aggression. 4- Feather pecking behaviour was not significant higher in high photoperiod group. 5- Egg production was lower in low photoperiod. In addition to egg weight was significant lower in low photoperiod although albumin, yolk and shell weight were not affected by the photoperiod. 6- Egg length, width, shape index and albumin height were significantly higher in control group. On the contrary, the yolk height and diameter were significantly higher in lower photoperiod. 7- Egg shell thickness was higher in higher photoperiod. B) Floor system: The obtained results of this experiment could be summarized the followings: 1-Feeding behaviour was significantly higher in lower photoperiod but the drinking frequency was not affected by the light duration. 2- Light duration was not affected on standing time, sitting behaviour but the standing frequency was significantly lower in lower photoperiod. 3- Walking and perching behaviour were significantly lower in higher photoperiod. 4- Feather preening and other comfort behaviour were higher in control group than other groups but the dustbathing was significantly lower in low photoperiod. 5- Aggression and feather pecking were not significantly higher in control group. 6- Egg weight was significantly increased with decreasing the photoperiod although egg shape index and albumin weight and its height percentage the were not affected by photoperiod. It significantly affected on all other egg quality especially egg shell thickness was increased with increasing photoperiod.