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.