I have (had) 4 two-year-old Leghorn hens. They get plenty of food, water, treats and time outside in a big run. Today a hen that has always picked her own feathers and had a hard time this winter suddenly died. No blood or injuries on the outside. When we picked her up, clear liquid came out of her mouth. I'm guess this was the water she had in her? I saw her two hours before she died and she was fine. Any ideas?