[the swiss chook]

Hi
I was wondering if anyone could give me a hand in finding out what's wrong with my chickens.
Living in Switzerland it's winter now and we have noticed a significants reduction in egg production.
thanks for your help
The swiss chook

[ghost61]

It's difficult to see what you are worried about from the photos.  Is it the spiny growths?  If so, they are new feathers and like mine, it seems your hens are moulting and so not laying (mine always stop at this time of the year as there isn't enough daylight hours to enable egg production).  If it's something else you're worried about, can you say what it is?

[Beekissed]

That's not molting...looks like parasite infestation.  Check them for tiny bugs around the vent and other places where the feathers are the most thin.  If you find nothing there, go out to the coop at night and see if you can see bugs on them and the roosts.  Some parasites live on them and some only prey upon them at night, but live in the wood of the coop. 

Egg laying slows down in the winter anyway, but a parasite infestation will contribute to that as well.