Actually, TRD, the difference between a chain on a bit and a chain on a leadrope, is that the chain on the bit cannot bunch up or go slack like that of a leadrope. The leadropes I have with a chain attached, have atleast 12 inches of chain. Wrapping that into a horse's mouth still gives it a lot of room to go tight and slack continuously (especially with lunging) and thus catching and pinch the tongue and potentially causing injury.
Chain can only conform to a certain point when pressed against an object, you're still dealing with a piece of metal - snaffle or not. While yes, I agree that if mishandled, the centre of a snaffle can come up and crack the roof of the horse's mouth, it doesn't mean a slack chain is any better.

Again, I doubt JackieE was using a chain bit at all, but the long chain of a leadrope that she was likely leading this colt with. Though I'm sure once she gets on here and replies, she'll be able to clear up the issue..

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