You have had many nice responses. One thing that worked for my son was frozen green peas. He would "gum" away at a few and they were too small to make me concerned about choking on them.
That was my oldest. My next boy loved the teething biscuit things. I had to laugh when he gnawed on them, smearing his face (all around the mouth), and I could imagine a clown face drawn on. :) These, I was cautious about leaving with him when they broke or became small pieces. Mostly these things (yeah, messy!) go from hard to slobbery to almost melting. So, I would take it away after a few minutes. He was a lot calmer by then anyway.
Please do not give your baby chicken bones (or any bird). These bones are known to splinter and even veterinarians recommend keeping them away from your pets for fear of choking or getting one stuck in their throat. They are quite the opposite of pork or beef bones.
Good luck! (I remember my Mom joking that I should dip my finger in some bourbon and swipe those gums! That is, apparently, what she used when I was a baby in the early '60s.)
D.