Some breeds of sheep (lamb) are very lean ! I think sheep has been bred for fatness. ... My cousin used to keep a flock of "Gotland sheep" A traditional "primitive" breed of sheep ,originating from the Swedish island of Gotland. This breed is primarily kept for the wool. They are primitive in the sense that they can thrive on marginal foods , are robust and only needs little care The meat was very lean - almost too lean - it had little taste compared to other normal breeds of sheep. Now my cousin has such sheep instead :-) Esben