When can I let them out?

[Vian]

I've got my chicken run finished. I covered most of it with some deer netting, but there are still some spots on one side that are uncovered. My chicks are almost 5 weeks old and they're getting feathers on their heads finally. I've been letting them out in the run the past few days for an hour or two while supervised and they really enjoy pecking at the dirt and finding bugs. They seem to hang out under the coop for the most part, but have been getting more adventurous and exploring a little farther away. They aren't using the heat sources in the coop anymore. I removed the heat lamp entirely, and I still have the heating pad in there, but they don't sleep under it anymore and only sometimes sleep ontop of it. Normally I would just have the coop open all the time with a milk crate under the opening for them to hop up and down onto to get in and out and just let them be so they can go in and out of the coop and run as they please, but I haven't tried that with chicks so young and I'm still a little worried about predators when they're so small still (mostly crows and other larger birds swooping down and picking them off, we don't have raccoons or foxes here in the 'burbs, but that's what the netting is for, to protect them from larger birds) I also worry about leaving the coop entrance open because it won't hold heat as well and I don't want them to get too cold.

Right now I have the coop entrance blocked off with a piece of wood screwed across the front that I'll remove when they're old enough to come and go as they please. What age is it safe to let them loose? I can also rig up a better "ladder" for them to get in and out of the coop with a board and some half-circle molding to make a ramp for them since I'm not sure they're big enough to jump on the milk crate yet.

 

[1muttsfan]

It would probably be best to shut then in at night until they are completely feathered and can tolerate drafts better. I would certainly shut them in at night until you have finished securing your run from predators. If for some reason they got caught out of the coop after dark they would be very susceptable to inclement weather.