Lots of lamb offal at Market Basket
The Somerville MB is replete with various lamb innards right now. Hearts, "guts" (intestines, I think), tripe, and bones are all available in large quantities. Presumably they come from same animals as the American lamb legs next to them in the meat case.
Just thought you'd like to know in case you're looking for a weekend project.
Market Basket doesn't butcher whole animals, the offal they likely purchase frozen. It is available post-Easter because that is traditionally when native lamb is slaughtered so there is a surplus and much other lamb is imported, so getting the offal is a bit harder (year round halal and other butchers break down native lamb, which are generally local animals).