I have hit several Turkey Vultures while riding. They hurt. I also had one "eject ballast" on me so he could gain some height
Fortunately, for that encounter I was driving a Toyota Forerunner at the time. A bunch of my long time buds were in the truck with me. At the same instant, we all realized what was about to happen, kind of like when you are in the process of slamming a finger in a door but you can't stop it from happening. We all screamed like little girls as I swerved in a vain attempt to get out from under it. No joy. There was road kill pooh all over the hood, windshield, and top of the vehicle. We arrived at our destination a few moments later, so it had not had time to dry. When I got out and made for the water hose, it was all I could do not to throw up in the yard. The other guys were all gagging and running away as well. It really is hard to describe just how putrid it was.
The thought of being hit by that while riding is ALWAYS present when I spot them while riding...