Twenty nine Farafra and Chiosram lambs 3 – 3.5-months-old averaging 18.93 kg were randomly assigned to three groups (9, 10 and 10 lambs) that fed 0%, 6% and 15% hay substituted the ration barley grains. Average body weight of Farafra eighteen lambs were 25.71, 31.84, 39.06 and 41.76 kg, at 18, 22, 26, 29 weeks of age and for Chios eleven lambs were 24.43, 29.23, 35.24 and 36.57 kg , respectively. Differences between body weights were significant (P< 0.05). Lambs received 15% hay containing diet, had the highest body weight, total gain, and average daily gain, moreover, 15% hay group had higher average daily gain being 208 g/d than other groups. Average total daily gains were 218 g/day for Farafra lambs and 168 g/day for Chios lambs. Lambs received 6 or 15% hay rations consumed less DM by 5.8 and 6.9%, respectively, compared with the control. Highest values of feed efficiency were for group 15% hay (5.88 DM), while the lowest efficiency value was for the control group (7.02 DM). Feed cost per kg gain when using diets containing hay was reduced by about 15.5 and 20.2 % for group 6% hay and group 15% hay, respectively. In conclusion, the use of concentrate diets with alfalfa hay level for early fattening did improve growth performance.