Very young baby lamb (about two weeks old, with a dressed weight of about 8 lbs.) is widely available in Italy. Lamb this size (occasionally called hothouse lamb) is sometimes sold in this country in Italian and Greek butcher shops, but older baby lamb, weighing 15-20 lbs. dressed, is more common. If you are able to find a 7-8-lb. lamb, roast it as in recipe below, but decrease final cooking time to 2-2 1/2 hours.