Best Use for Acorns?

I finally got my second acorn and I've been given an option to offer it to a woodpecker. I gave my first one to a opossum but it didn't seem to do anything, is there a guide anywhere about what they're best used for or should I just sell it?

I haven't memorized every interaction with it comes to the acorns, but the most use I have gotten from it is using it with the prairie chicken. Once you unlock the prairie you have the option of giving it to a prairie chicken and it gives you a carcass that has a chance to be a large one. I've gotten a few small ones, but it gave me a bison once.

I don't believe there is a guide for all acorn interactions yet though, but most that I have encountered typically give a few SC or a lucky foot in return.

What's a lucky foot do?

Lucky feet help you in battle, though they don't guarantee a win. I usually use them on high level enemies or when I'm getting low on health to give me a helping hand in the fight.

wow that is pretty useful, i guess I'll save it then in hopes I can get one of those! 

Here's a guide for all encounters, just search it for acorn!  https://www.wolvden.com/chatter/topic/61

(also note that some of those only show up in some biomes you may not have reached yet)

I think the bluejay is the best (you get either a lucky foot or a high-use toy).