Beginning an animation from a random frame.

Hey guys, I'm sure this has been asked before but I'm completely new to C# and unity in general. I've looked over a lot of responses to similar questions and simply don't know how to implement them. I've got a textured model, and I've made an animation for it. The model is a fern and many of them exist in the game world. What I'd like to achieve is to have all of the ferns play the animation of them swaying (which they do) but not in sync, so basically just have them all start the animation from a random keyframe. Is there a script to do this? I've really no idea how to code in C# (but I'm trying to learn) or how to begin it. Thanks everyone :)