Do adult cochins FLY? Ours haven't made it to that point yet (they are still eggs, LOL) - but I'm thinking of keeping them & my Indian runners in the same pen w/my goats, which has a 3' wood/mesh fence. As long as I make sure they can't get UNDER the fence, do I have to worry about them going OVER once they are full grown? I know there are always exceptions, but - in general?