Excepted from an Interview with Nick de Toldi at www.gourmetfly.com
There is only the need to buy the most prime and expensive cut of lamb for the sort of dishes such as Rack of Lamb or the famous “Baron d’agneau de Pauillac”, a roast including the 2 legs and the “saddle” typically served at the prestige dinners of the wine chateaux beatween Margaux and Pauillac.
But, I explained to Nick that in Colorado, we frequently encounter Basque sheepherders while hunting Dusky Grouse and Sharptailed Grouse here in September. And, their sheep are eating nearly a pure diet of sage brush, which is very strong-tasting. The mule deer that come from the mountains are very strong and gamey as a result of this same sage brush diet, as compared to our white-tailed deer which feed off of the farmer’s grains of the plains.
I compared this to our farrier who raises a special breed of lamb for the table and sells them by the whole or half. They are pricey, around $300 to have a whole one butchered and packed. He feeds them a special diet to have them fattened and the best tasting, and they are harvested while they are very young. 
He reiterated that for the slow braised dishes, you want the heartier and older lambs, while for the quickly cooked chops, you want the young corn-fed or grass-fed varieties.
