I will simply repost - it is solid and all that needs to be done
I will update that post and state the constant temperature essentially means they need to be warm - if you can keep that temp around 75 F or a little better you will be very happy - warmer is fine but not really required in your case.
Put a couple of lights in the coop that provide regular white light and put those lights on a timer - red light is ok but not good enough.
Or use white light heat lamps - still a stop gap measure but an improvement.
Keep them warm, give them light, feed them well and provide lots of clean water - they will lay
You are part way there
Cheers
BC
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While most of the experience I talk about comes from broilers that my wife was involved with - I can say this with a fair degree of certainty.
You need a constant temperature, good feed, clean water and controlled lighting to make any headway with birds. Free range may be nice - but they are not likely designed to do this AND lay eggs under the present conditions. Time for them to be indoors if you want eggs. Or leave them out if you are prepared to do the welfare thing until it warms up and the days get longer.
Yours are simply in survival mode - too cold, too dark and probably because of it they are not eating and drinking as they would normally - so - no eggs.
Warm them up, give them more than 16 hours of light and you will see a difference in their eating and drinking - and eggs will come.
Age is also a factor - you get them as chicks or birds?
Chicks - well they may be coming to the end depending on the breed and the living conditions..
Birds - they may have reached it.
Chicken soup or stew is the best and layers are tough to eat after roasting.
Yes older birds will lay - and lay well - they just need a bit more care.
Sounds like these might need it.
Good luck
BC