Hi there. You really need to get him to the vet today i'm afraid, as chicken bones are very sharp and can do a lot of damage to the back of the throat, they generally do not dislodge themselves either, due to their sharp nature they tend to get stuck in the soft tissues.
Your vet will need to sedate him, so they can get to the back of the throat and remove the bone without causing any damage to the surrounding structures. There are many vital structures in the throat so its very important they are not damaged.
If you've not already done so, ring your vet and get an appointment asap. We don't want to risk any damage to his throat by hesitating.