Wiring over the top is a great idea, it will protect them from hawks, owls, raccoons and oppossums. Besides some roosts and nest boxes, the only other thing I would do is some sort of roof over part of it to give them shelter from the rain. Keep in mind that babies don't usually roost and they start out roosting low. My grower pens have nest boxes on ground level for the chicks/juveniles to sleep in so they can get off the cold, wet ground. A partial roof will be helpful in keeping your feeder dry too.
We will be adding a roof soon using clear roof sheeting. We have one wall left to put a wire barrier down underground at the front and the roof and we are finished! All except the roosts and nest boxes anyway. The chicks are roosting on a little dowel in the brooder now, so we will put in a temporary low roost for them to use. I drove by a warehouse today and spotted a nice wooden box. It should be the perfect size to make two nest boxes for the girls. I will either let them sleep in it until they start to roost to sleep or I will put a smaller plastic tote on its side for them to snuggle into.
I don't have plans to leave the chicks outside at night just yet since they are only 3 weeks old today. I am going to give them at least another week inside at night- especially as cold as it has been getting this week. They are feathering nicely, but not quite there yet. Should I be acclimating them to the colder temps. I have a heat lamp on them, but it has been getting @ 70 -ish in the brooder first thing in the mornings.
Another question- the coop has a dirt floor. I was thinking of adding some pine shavings to make it easier to keep clean. Any suggestions?