Hen sits in the nest box but doesn't lay any egg

[MaeM]

So, after an IBV outbreak in my flock, my remaining 3 hens have pretty much stopped laying eggs. They're only 3 years old, so the vet thinks they may have an atrophy in the ovary, as the virus "likes" to attack the reproductive system as well as the respiratory system.

And in fact, at least one of them has atrophy in the oviduct as she lays either soft-shelled eggs or deformed eggs, but not every day.

What's new about this matter is that I see her sitting in the nest box, even though nothing comes out of her.

She spends a while in the nest box, comes out, goes back again, etc. I keep checking the nest box and there's no egg, no yolk - nothing.

But then why does she act like she feels the urge to lay an egg?

Any explanation? I'm super concerned about internal laying as her sister died from that.

 

[azygous]

I've had older layers do this. It can be simply from habit. Or the hen may feel an obstruction which stimulates the urge to lay an egg. It's not easy to tell one from the other. If you continue to find her on the nest, you might pop a calcium table into her beak just in case an egg is stuck. It can help strengthen contractions.

In extreme cases, a hen that is winding down her egg laying career, can get an egg stuck and in straining to push it out, she may suffer vent prolapse. You may want to take a peek at her rear from time to time to be sure that's not happening.