The present work aimed to study the effect of Rayeb milk as a probiotic on the growth performance, behaviour, and cecal lactobacilli count in broiler chickens during the starter phase (0-15 days). One hundred and twenty 1day-old male broiler chicks (Ross 308) were allotted into two treatments 1) control group (drinking water only); 2) Rayeb milk group: 10% Rayeb milk were added in the drinking water. The results indicated that Rayeb milk supplementation had no effect on the body weight and body weight gain. While, there was a significant reduction in feed intake and improvement in feed conversion ratio of Rayeb milk treated birds in comparison to control. Also there was a significant decrease in feeding, resting, and dust bathing activities, and a significant increase in drinking water activities of Rayeb milk treated birds in comparison to the control. While there were no significant changes in walking, standing, preening and wall pecking activities between Rayeb milk treated birds and the control. In addition the results showed that there was a significant increase in total lactobacilli count in Rayeb milk treated birds in comparison to the control one. In conclusion the current preliminary study reflected that dietary supplementation of Rayeb milk may improve the health status and reduce the production cost of the birds. However, further investigation is still required to determine the best dose before it could be applied in the field.