What’s on my hen’s comb?

[nuthatched]

Looks like dried blood to me.
Do clean her comb if you want to, so you will know for sure!

...She is a beautiful hen. I love the colour of her feathers...!!
And indeed, she looks very healthy.

If you are right and she is overweight, it is probably the reason why she does not lay eggs anymore.
But there happens to be some hens that stop laying without a seemingly obvious reason, and so, we don't know exactly what the problem could be... so could be genetic, or whatever...

You could want to try mixing some food grade Diatomaceous Earth in her feed, everyday, just to see if it could make her laying eggs again...
Sometimes, some hens sadly need help to do their job!

(What are you feeding her?)

Adding DE won't do much of anything except cause long term respiratory issues in a bird's delicate respiratory system.
Light, hormones and protein are essential for egg laying.
Most feeds contain 2% de to prevent caking, any more creates dust.