I am new to the chicken world and after reading this blog, I am wondering if my girls are safe in their coop. I have them inside of a large dog pen that is about 6 feet tall. Since they are young, they have a smaller pen inside that snugs up the their coop. But, as they get bigger I plan to take out the smaller run and let them have the whole pen to enjoy. Do I need to re-enforce the top as well as I did the sides before I let them go?