Hen stopped laying and is not eggbound, otherwise normal

[veetown707]

I have a 3 year old Red Star who was rescued last year from a factory farm. She had lots of broken feathers at the time and was underweight. Since then she recovered many feathers but didn't do a full molt in the fall. She was laying almost every day as normal. She hasn't layed an egg in a few weeks now, but is not eggbound as far as I can tell and has normal temperature, normal energy and appetite. In fact she's even gained weight and is perkier than ever.
We did have a week where it was colder at night than usual, however we insulated the coop and no one else stopped laying but her. I'm at a loss as to what could be going on as she seems to feel great otherwise and is still very young. Any thoughts?

 

[sourland]

Not unusual for a bird - especially one that old - to take a break in her laying cycle.

 

[veetown707]

Not unusual for a bird - especially one that old - to take a break in her laying cycle.

Really? I've been raising chickens for many years and I've never had one this age stop for this long unless they were molting.