They are about 5-weeks old now. I have them in the tractor during the day, but it is not huge. I think they might enjoy roaming around the yard when I am watching (fully fenced yard, about 4-feet high picket). Is this safe? Will I be able to catch them and get them back in the tractor when I am ready? I am a city girl, new to chicks, so I am not always sure what is ok. I would hate to injure or lose them!