Why are my orpington hens roosting in their nest boxes

Sometimes young birds will do that because they feel secure in the small space. You'll have to go out and put them on the roost to get them used to being up there. Just wait until dark and then go out and move them.

 

Are they laying in them. I would block off the nests at night with something and reopen at dawn

 

Mine still continue to do this. We allowed them to do it as chicks in order to stay warm, but now they always sleep in them and make a big mess. So every night I have to go and put them on the roosts, then they stay there the rest of the night. I would either block off the nest boxes or go in at night when they are asleep and put them on the roosts.

 

Block off those nests and make sure your roosts are higher than your nest boxes. I had this happen at first too, but they will learn quickly and after they see how nice the roosts are they won't go back to the nests.

 

I'm having to block off my nesting boxes too at night. It seems to work best. It'll take a while (this also helped break a broody hen) but they will get used to sleeping somewhere else.