What dimensions is it?
Pics of the outside where the lil guy is choosing to roost and farther back to show more of the inside please.
I see you have a nice window installed. Any vents to go with it?
So a very young cockerel?
Yeah stuff his brazen butt in the coop so he learns that is where to sleep.
Speaking of coop.....sometimes there is a real reason they don't sleep inside. Pics of your set up and number of birds will help. We may see something that is easy to fix that is stopping...
Is this the male chick you posted about very recently?
This is the tread I am recalling.
https://www.backyardchickens.com/threads/intoducing-blind-pullet-to-existing-flock.1397718/