Walter, first time out for mine is usually when they are still only walking about and only for 5 - 15 minutes. Once they start flying, it stretches a bit, but by then they know their way out and in. I once moved a YB that had been bred for a sale over into the YB end so it wouldn't get scalped. I was in a rush the next day and just opened up the YB's. I thought I would be ok since it probably wouldn't find its way out and if it did it would stay with the others. Whomever bought it would have no problem breaking it because it had only been out the once. When I returned home I had one YB missing, yes the less than four week old for the sale. Finally had it reported about two weeks later by a non-fancier in Ceres, Fife. With help from this site I got it back and it is now in the race team. I hope its experience serves it well. At least it managed to escape what I can only think was a BOP attack.