I don't know what the laws are like by you regarding traps and guns and wildlife, but I think you should get a gun/trap and sort this creature out yourself. If you can. This is nonsense, waiting around and having to babysit your hens. You are stressed, the chickens are stressed... I'm not pro guns or killing creatures, I just told another member here we lost 32 chickens to predator attacks before we declared war on them. But there's no pint waiting for that thing to come back, and it will. It knows there is food and it's an easy target. You are not going to sleep easy until this is sorted, so I hope you get it sorted soon. Good luck!