I have a 10x40 yard free range that I have kept meat birds chickens in every summer. I tilled and planted alfalfa and clover 5 years ago. Now it is 50% grass, 25% clover, 25% various wild meadow weeds. I can raise 25 Grazers (Freedom Rangers) and they do well without destroying the habitat I want to try ducks. Thinking about 10 Pekin ducks. Is this 10x35 yards enough territory for them to graze without destroying all the vegetation?