Ever see those bags of corn that are available to feed wildlife; squirrels etc. Do those ears degrade?
Everything that was once alive will compost.
How fast it composts depends on your concept of speed. I've never found a corncob in my compost. I just swapped my "live" pile for the empty bin that was spread on the garden. The pile I just moved will now rest until next year.
Big chicken bones not in the center will last through the year. Hambones will go 2 years. Avocado pits will last a year if they're not in the center unless I split them in half. Everything else (excepting sticks) will break down in 1 year.
Slowly, as mustard seeds has said. You can speed up the process by chopping them up when you add them and/or when you find the partly decomposed ones in your compost.