Two of my pullets have stopped laying. I watched them carefully today, they are not eating the layer crumbles unless I make a wet layer mash with yogurt or scrambled eggs. It's as if they have very little appetite. They do scratch around in what's left of the grass in their lot and eat dried grass, etc. I can see pieces of undigested vegetation in their poop, which is watery. They are 8 months old. Both have been a little sluggish lately and maybe this is why. What can I do?