We have 5 hens from 25 weeks to a year old. We would like to let them free range--but don't want to leave them out unattended--but when we did the young ones were hard to corral and get back in the run. I was thinking of every time I bring them snack food in the morning or treats later in the day I would blow a whistle. Hopefully after a while they would come running when I blow the whistle. Is this remotely possible or just a dumb idea?? Hoping for a Pavlov chicken theory.