Or you could realize that bones are delicious...
Seriously though, I think people are way overreacting to the "mysterious contents" of fast food. The study about how there's beak and nerve tissue? Did not use an adequate sample size, and those that do find that it's not a very common occurrence. You might say to that "one time is too many", but then I point out that they are still using 100% animal parts....which should say something.....and how we use the things that we are grossed out by all the time in cooking. It's not bad for you. It's not dangerous. It's actually delicious. Have you ever had bone marrow? It's delicious. And yes, you have. Any time you eat/drink something that is made with stock, you are having bone. It's the bone that makes stocks delicious. You cannot realistically expect that no bone gets into processed meat. Because the meat is attached to bone, and getting it off requires scraping some bone off. This is even more common with hand butchering, because the machines are better about getting meat without as much bone. Which brings me to the "pink slime" which is literally just meat. It looks weird, yes, but it's still, 99% meat. The other 1%? Stuff attached to meat (tendon, bone, cartilage, etc.). Negligible amounts of other stuff (air, water, and yes, ammonia, in small enough quantities that it is impossible to detect without specialized equipment).
Now, having said all that, most fast food still sucks, but it's because it tastes bad and is poor quality and nutrition value. Not because they don't use food.