In this study, the behaviour responses of the crossbred lambs [F-2 (German Black-Headed Mutton x Merino) x F-1 (Chios x Kivircik)] were compared with the Kivircik lambs in intensive conditions and the effects of genotype, sex and observation period on the behaviours displayed were investigated. The data were collected from 10 (5 male + 5 female) Kivircik and 10 (5 male + 5 female) crossbred lambs, which were weaned at the age of 2-2.5 months.The effect of genotype was found significant on the behaviours of feed consumption (P < 0.01), activities towards the bedding material (P < 0.05), rumination (P < 0.01), lying (P < 0.01), oral stereotypic behaviours (OSB) (P < 0.01) and behaviours towards animal (BTA) (P < 0.01). Behaviours towards other animals and oral stereotypic behaviours in the crossbred lambs were 50% and 27% more than the Kivircik lambs, respectively. Significant differences in terms of the activities towards the bedding material (P < 0.05), rumination (P < 0.01) and lying (P < 0.01) behaviours were determined between the male and female lambs. It was seen that the male lambs were more active in the breeding area. The effects of observation period were found significant on feeding (P < 0.01), drinking (P < 0.01), rumination (P < 0.01), lying (P < 0.01), standing (P < 0.01), oral stereotypic behaviours (P < 0.01) and behaviours towards animals (P < 0.05).