Greedy Chooks !

A couple of months ago a sack of feed would last a week, now they are going through two sacks a week. Nothing can get in the run to help them eat it and  we dont leave any food out overnight, so i am assuming that they eat more during the colder months to help themselves keep warm. Am i right in thinking this?

Should be OK if they're eating layers pellets ... it's too many treats that will pile on the weight and slow egg production!

A couple of months ago a sack of feed would last a week, now they are going through two sacks a week. Nothing can get in the run to help them eat it and  we dont leave any food out overnight, so i am assuming that they eat more during the colder months to help themselves keep warm. Am i right in thinking this?

Its too many treats that make them fat! Layers pellets should be available to them ad lib, they will only eat as much they need. It makes sense that they will eat more in the winter as you use more energy in the cold keeping warm. Also, mine free range in the aftrenoons, and in the summer they have far more goodies in the garden than they have in the winter, so maybe they are having to eat more pellets because there is less greenery in the garden. ...Im pretty sure that layers pellets dont make fat hens, so dont restrict them, they will only take what they need.
I know you have said nothing can get into the run, but you would be surprised...have a really good look around, look for tiny holes. Does your run have a roof on, what width are the holes in the mesh?, a pest control man told me that if you can fit a pen through a hole, a mouse can get in , we used to keep rats as pets and believe me they are pretty agile aswel