Liz, any maturity associated with the beard comes from the food particles lurking there (and possibly the goose-shit!), and most definitely not the wearer.
I don't know much about what comes out of the rear of a goose (save that it's hellishly messy) but goose-shit green is a recognised colour - ask any tailor. Comes from the days when colours had more robust names (I mean, what the f*** is 'Sunset Blush' or any one of the millions of bloody names on colour charts these days?). Much like good old DSB for painting woodwork - which, as any old-school decorator will tell you, is dark shit brown.