I've one, perhaps two hens (3 years old) with sometimes loose droppings. Instead of a firmer dropping with white top, it's a bit loose with the white top. In the morning, the poop is fine. I clean the coop out each morning, and the droppings are healthy appearing. But in the afternoon, they become loose. Sometimes really sloppy... They are backyard hens, and eat a lot of grass besides their regular Layeena and a few treats. No pesticides or other chemicals have been used anywhere in the yard for years.
The grass doesn't seem to be well digested in the droppings, so I'm assuming the food is just coming through the intestines too quickly.
I've a third hen who is having trouble getting around because of her arthritic legs. She doesn't eat nearly the amount of grass/feed the other two do. Her 'fertilizer' is fine.
I generally give the hens 1/3 cup of raw oatmeal, with a little water soaked into it when I put them into their run in the evening. They also have spaghetti, veggies, raisins, crickets and other goodies. Sometimes in the oatmeal, I stir in a fresh, raw egg. Nothing that's really junk, like doughnuts. :)
So... any ideas? I'd really like to get back to nice looking chicken fertilizer instead of this sloppy stuff!