Chickens won't go into coop at night!

[Margot-chick]

Our 3 chickens who we have had for a year have always taken themselves into their coop as soon as it got dark, however for the last few days the 3 of them have been perched on the roof when we have gone out to lock them in. We have had to lift them in as they have been very reluctant to go. The weather hasn't changed much and the coop is clean so we're a bit stumped as to what's going on. Any thoughts would really be appreciated.

 

[Firekin1]

Any possibilities of rats getting in or possibly something else that could have spooked them?

 

[Margot-chick]

It's possible Firekin during the day when they are out in their run that rats could get in but its empty when we put them in at night and once its locked nothing can get in at them. They are still using the nesting box to lay which is in the coop. I'll keep my eye out though thanks.