Never tried broad beans or shells, I've not heard that they are no good for goats. I had a neighbour who always grew too many runner beans, when they 'got away' from him he used to give me loads whole which the goats relished! At the end of the season he pulled up and gave me the runner bean plants and I threw the huge bundle into the goats paddock, the goats cleared the lot in quick order!
The only thing I didn't feed them was Brussels Sprouts, they taint the milk terribly!