Hello. I'm making an isolation type area in my coop so that my silkies (when they get here) will have their own little haven from the full-size ladies. I want to make a door that they can get thru but the other hens can't. Our coop door is 11x15 and two of them bust out at a time... would 4x6 be ok? Or is that going to be too small for the silkies?