I built a screened cover yesterday with some chicken ire sandwiched between two wooden frames made of 1"x2" lumber I had on hand. It seems to be working fine. Hopefully the weather starts to warm up so I can get them in the coop, which is nearly finished. I just need to get another piece of plywood to complete the roof and some hinges for the door, roof hatch, and roll-away nesting box covers.Love the pic, & yes, they're getting bigger! I'm surprised they didn't learn how to escape sooner. Mine usually hop out during week #2 if I don't have a lid. That's why I always tell the teachers not to keep chicks past the 1st week.
However, your chicks seem to be even more advanced. Make sure to hide your keys before the little ones learn how to drive themselves to the feed store for treats.