From everything you have typed in...... I would guess that they aren't getting enough food. It is amazing how much more they eat in the winter.
I greatly recommend feeding free choice.
If you have a big rodent or whatever problem, then put out the food first thing in the morning and take it away every night.
With temperatures that low, some extra meat and fat is good. Mine get my bacon fat, they love it.
Not sure if light is a problem.... My chickens are in a very dark shed, they CAN go outside if they want to, and their water is outside, so they do have to go outside to get the water, but I only very rarely see them outside. Point being, my chickens do go run out and see dim sunshine, but only in very tiny amounts.
I do think that being locked up all of the time is bad simply because most coops don't have enough airflow. Ventilation is so very important.
If you have no run at all for them, there is the problem that if you let them out, that something will eat them. I would get 7 or so free pallets, lash or nail them together to make a small secure run, and give them access to that during the day.
Don't forget to trade out the plywood that you have on top of the chicken tubs with something breathable like net or fence.
I greatly recommend feeding free choice.
If you have a big rodent or whatever problem, then put out the food first thing in the morning and take it away every night.
With temperatures that low, some extra meat and fat is good. Mine get my bacon fat, they love it.
Not sure if light is a problem.... My chickens are in a very dark shed, they CAN go outside if they want to, and their water is outside, so they do have to go outside to get the water, but I only very rarely see them outside. Point being, my chickens do go run out and see dim sunshine, but only in very tiny amounts.
I do think that being locked up all of the time is bad simply because most coops don't have enough airflow. Ventilation is so very important.
If you have no run at all for them, there is the problem that if you let them out, that something will eat them. I would get 7 or so free pallets, lash or nail them together to make a small secure run, and give them access to that during the day.
Don't forget to trade out the plywood that you have on top of the chicken tubs with something breathable like net or fence.