I am "fairly" new to this chicken game, at what age do you all let your chickens out to free range for the first time, is it based on age or clearly their size? I have 16 8-9 week olds, one is a silkie bantam, so smaller then the rest....I would love to let them out of the run and coop area, but am still unsure of the ages it is considered safe? Does that make sense!?