Lethargic isn't normally good sign but they might be cold. Mine sit on the snow to conserve body heat. If you can post pictures someone might know the breed. Are they free range - you can't control what they are eating if they are. Mine are half free - they are in a large run and I feed mine layers pellets, raw left over veges, porridge with milk an honey, couscous, rice, plus they eat any insects and other beasties on the ground as well as earth/grit. My ex battery hens are very friendly, my light Sussex are scaredy pies. Strange thing is Sussex were hand reared, batts have little human contact while at the farm.