I have a flock of Guinea hens that is slowing being eaten by hawks. Every couple of days the hawk comes and attacks one of my hens. My Guinea hens are free range and I want to leave it that way, they help to rid my yard of ticks and other unwanted bugs (i.e. the # of japanese beetles in my yard has significantly declined since I have gotten my Guineas. What can I do to keep my Guineas safe while free ranging?