What I expected to happen was...:
That chicken-riding (which is amazing, by the way) would be a painless endeavour.

What actually happened was...:
Generally when the chicken flaps around a corner, the baby pigman will make a noise of pain.

I assumed that the chicken was causing him to glitch into walls when it was flapping. He never stayed stuck in the wall – he stayed on the chicken and it kept moving.

I do not have a mod on that shows me the HP of mobs, so I do not know if he was actually taking damage or just making the noise.

Steps to Reproduce:
1. Follow a baby pigman on a chicken around for a while.
2. Especially try to follow him around on full block stairs that go around a few corners.