I have 26 ten-week old chicks on chick crumble and they really want to get out and explore. Is it wise to release them into a fenced area to scavenge for grubs and seeds and such? I don't want them to mature too fast. If it is not a good idea, then at what stage should I release them into the open? I intend to transition them to "developer" in about 4 or five weeks time.