I am very sorry,
I beleive 50 chickens is way to many for that size coop
30 chickens would even be alot.
I have a book it says 8 x 12 can only handle a maximum of 30 chickens
Even 30 chickens in a 12 x 12 is quite crowded.
I would definitely let them free range or build a bigger coop.
And...