What I expected to happen was:
When I press shift and right click the top of a hopper, I thought I see a fire that can kill all the chickens sitting on the hopper.

What actually happened was:
All the chickens burned to death, but I didnt see any fire on the hopper. So it seems if you put fire on a hopper, its INVICIBLE! or.. I am a wizard! (guessing the last one)

Steps to Reproduce:
1. Place down a hopper.
2. Take Flint and Steel
3. Point your cursor to the top of the hopper.
4. Hold down SHIFT
5. Press right cursor button.
6. and you start hearing the fire burning but you can not see anything. You can spawn animals on the hopper, and they will burn.

I have tested to do this is multiple worlds with survival and gamemode. It is definitely a bug.