She was fine yesterday morning when I went down to feed and water. She was eating and being her friendly self. After I did all my usual morning tiding up the coops and runs. I lock them in and went to do some yard work. I went down at 6 that evening to let them do some free ranging. I thought it was odd they were not at the door waiting for me.instead her three sisters were gather around her. She must have died soon after I lock up as rigor mortise had already set in.I pick her up and my husband and I check her over no puncture wounds her vent area was clean. She was one of my favorite hens she was 16 months old. Isa Brown Their run area is very secure so I was not worried about any predator causing her death.My thoughts was a heart attack. I noticed back in the winter months that she would be walking and come to a stop. She would lift her wings and pant as if she was hot. I have spent a sleepless night crying over her loss. And wondering what really happen to her. This morning I did kill a black snake. within 5 feet were I found her. He was in a small tree that I planted in the run years ago.I heard a bird screaming and the black snake and bird fell from the tree in a ball. The snake was wrapped around that bird squeezing it to death. I ran a got a hoe and took care of that snake. The little bird flew away. Now I am wondering if that snake could have choked her to death.