We've been having an egg quality issue with a couple of hens in our backyard flock. The eggs, which appear fine from the outside, are a watery mess when you crack them open. The yolk is not formed and when you crack it into a bowl it all comes out in a watery mess of yolk and egg white. We collect our eggs everyday, the shells are not deformed, they egg doesn't stink or have a strange smell, it just looks pre-beaten. None of the hens looks ill. Has anyone had this happen before?