We had a similar experience October of 2011. My chickens were out free ranging and a bobcat got one of them. My mother's screaming and arm waving frightened the bobcat away, leaving the chicken behind, but it died moments later. We saw the bobcat several times over the next week and I kept the chickens in their run. In December I flew to Memphis and purchased a 9 week old Anatolian Shepherd puppy and drove him back to Colorado. While I have not raised him to be a true livestock guardian dog, we spent about an hour outside with the chickens and our other dog every day when he was a puppy (cold during the Colorado winter) while the chickens free ranged and now I tether the dogs outside for about an hour a day while the chickens free range. Aslan, the Anatolian Shepherd is very much on duty during that hour, on his feet and barking at stuff he sees/smells/hears or perhaps just suspects is out there. However, we have not had a any more losses while the girls are free rangeing.