Diurnal patterns and time courses of activity were investigated in groups of fast-growing broilers subjected to different levels of qualitative and quantitative feed restrictions. Eight groups of 225 female Ross 208 broiler chickens were reared from 1 to 57 days of age in straw-bedded floor pens (18.9 m2) equipped with drinking nipples and six circular feed troughs. The lighting schedule consisted of 7 h and 10 min of darkness preceded by 30 min dusk. Groups were fed one of two feeds (Control and Diluted), where the latter was the control feed diluted with 15% ground oat hulls. All groups were fed ad libitum between 0-7 days of age and 43-56 days of age. During the in-between period four groups were fed ad libitum and four groups were fed twice a day (meal-fed). The meal-fed groups were fed 58 and 67% of the ad libitum groups on control and diluted, respectively, calculated on a weekly basis. Activity was logged every half-a minute throughout the experimental period using passive infrared detection (PID). Number of birds feeding was counted in all groups every 4 min during 90 min after the morning meal (08.00 h) and 90 min around the afternoon meal (14.00 h). Quantitative, but not qualitative, feed restriction affected activity levels, with meal-fed chickens being more active throughout the light period. An increase in the proportion of meal-fed birds feeding following each meal was observed. Across the meal-feeing period the meal-fed chickens appeared to learn about food availability and adjusted their behaviour accordingly. General activity of the chickens peaked at 21 days for all groups. An activity increase during the dark period was found to reflect night feeding as well as the growth of the birds. The potential welfare benefit to the birds of increased activity caused by quantitative restriction was in the present experiment overshadowed by the concomitant extended periods of hunger.