Roosting in the nesting box

[GSPx2]

Since it started getting cold my hens have been sleeping in the nesting box. I figured it was because of the hay in the box so I placed hay in the coop but they keep going in the nesting box. Any ideas on what I can do to keep them out?

 

[Kelsie2290]

If putting them up on the roosts for a day or tow doesn't work, I usually block off the nesting box they were trying to use in the evening when I gather eggs. They had been using the roosts before? With it getting dark earlier, are they going in when there is still some light or are they going in after dark? The roosting area is draft free and they are able to get on and off easily?