please, need ideas for quick temporary housing for he and her babies

HI,
My hen is hatching out her eggs....8 chicks so far,16 eggs.
I have a cage about 2 ft. by 4 ft. metal frame.1 inch chicken wire that we put over her......
She is setting beside the house otherwise unprotected.
I would like to get her in the barn where she would be easier to care for.
I have a problem with rats and squirrles.
Thinking about pegboard??????????
Just not sure what is safe and how much room they need.
Thank You