Barnyard usually means wet. I like my maduros same as you, and that's normally a good indicator I'll like a cigar. Trouble is, when I smoke them wet, a lot of ammonia comes along with it and just plain ruins the flavors of the cigar on retrohale. All I get is burned out noseholes.
So I set them down at 60% for about 8 months. At that point, the barnyard tones down a ton, and the chocolate, sweet, spicy, full delicious flavors come out.
Here's a tip...
If you like that barnyardy wet smell, order any Oliva maduro from the online vendors. They always come super wet and fresh. Special G maduros, G maduros, and especially O maduros will totally rock your world. The longer you keep them, the better they'll get, too.