I run 24 chickens on 0.33 acre and have to mow every week.I would think that 9 chickens would scratch up a .2 acre plot pretty quickly. if they're on it all day every day. The goose will of course also eat grass but not scratch.
The only approach that might work would be if you were able to use temporary fencing to get the chickens into one small space at a time and rotationally graze them.