So sorry for you loss. I don't free range because of losses in the past. I built nice large covered pens with good heavy duty netting. I have electric wires around my coops and pens and concrete under the gates all due to losses from predators in the past. When free ranging, it's a risk you take and you will loose birds sooner or later. I can't be out watching my birds all of the time but I have peace knowing they are safe. People get joy from watching their birds out free ranging but the minute you get distracted a predator may strike. If you have a camera, put it up because most likely the predator has been lurking looking for an opportunity and apparently found one and it will be back. It could have happened by but most likely lurking. You may not see it but it probably will see you. Good luck...