Left over cedar planks?

I have a ton of 1x4x6's cedar planks left over from my fence. How can I use them as siding when they don't line up exactly? Any ideas how to make it weatherproof? Thanks.

 

We're going to try the board and board method!

 

Yeah! We're trying to buy as little material as possible. So we'll see how well sealed the board and board works. We might even use some silicone if there are few enough gaps. We're also worried about adding osb due to the structural support as we're putting a green roof on it don't want it to be too heavy!

 

Thanks for the advice. I've done some research and everything is hearsay ranging from instant death to they'll be fine. Facts and research are hard to find. From what I can tell, as long as it's aired out wood, plenty of ventilation in the coop, and cedar lumber (not shavings or the closet liner stuff) The chickens will be ok.