Chicken bones can be especially dangerous because not only can they cause an obstruction of the bowel but they can also splinter causing a puncture to the bowel, both serious conditions.
For now what I would do is give him three or four pieces of whole grain bread to try to build a cushion around the bone so it does not puncture the intestines. Then you will need to watch for him to pass it. IF it cannot pass then you will see signs of an obstruction which will be sudden lack of appetite, vomiting, change in stool and habits, and lethargy. An obstruction would require surgery.
If it just happened you can bring the dog to a vet and they can try to retrieve it with a scope, preventing surgery.
Here is more on obstruction.
dangers of bones http://www.thepetcenter.com/imtop/bones.html