I have a question. I have a Jersey Giant. It took me awhile to figure out who was laying double yolkers, but it is our biggest girl. All spring I fed pelleted layer. And then, I had a duck get lame, so I've switched to Flock Raiser and added oyster shell for the hens. OK, so all spring, I would find no shell eggs that were consumed. After I added the oyster shell, we had the biggest double yolk egg ever. Since the oyster shell, no more soft shells. So I guess that girl needed more calcium than the others. This morning, I collected an egg that was coated in yolk. And there was yolk painted on the shaving. I found the girl with the yellow butt and it was no surprise who it was. So I guess, she had a yolk in the canal in front of the egg with the shell. Is that yolk residue going to cause issues? Any questions?
When I find yolk residue it usually means an egg was broken and eaten, I don't think it's possible for them to lay a yolk only, perhaps your girl sat on what was left from a broken and eaten egg. Many younger hens will lay double yolk eggs, as well as an occasional shell less egg. Switching from a lower protein layer to a higher protein all flock would boost production, it's one reason I don't feed a layer anymore.
This was an egg coated in yolk and yellow on the shavings. No egg membrane like I usually find. And the egg was warm, so I collecting right after she laid it. I looked for the yellow butt and it was the same girl that has been laying the doubles. It's weird. All I can figure is there was a yolk and possibly it broke before the real egg was laid.