Wet meadow native grass in barnyard
My barn sits on a hill, at the bottom of which is a wet meadow that leads into a small pond. The barnyard, with chickens, ducks, and geese is on the hill. The waterfowl parade to the pond a couple times a week, in good weather.
When the snow melts, I'm looking forward to bare spots and mud.
My plan is to rotate various parts of the barnyard for the birds' use, while other areas heal/grow up.
So, here's the question. What sort of natives (mostly grass, likely, but wildflowers too if they make sense) should I try to grow, here? They should be durable, fast growing, nutritious for birds, thrive in a heavy nitrogen environment, and able to stand wet feet (their own and the birds trampling!).
Sources of seed would also be appreciated. The area is about 2500 square feet.
I'm zone 5, central MA.