We have 7 chicks approx. 4 weeks of age. They have been in their coop with a heat lamp ( on and off depending on the weather) since we got them 3 weeks ago. There is a spacious enclosed run connected to coop that is gated off to them. Any reason why we can't let them out to get use to the run at this age? We would round them back and into the coop after their outing and play time. Thanks for any input.