Hey! Did I miss it, or has no one mentioned the soft rubber “dogbone” or “sausage” bit (used to be called a “breaking bit” in fact)? Goodness, I start most of my fillies in them and one six-year-old I recently sold was still in hers (and went in a similar dogbone-styled pelham).
If you aren’t familiar with this bit, it is so soft that you can bend it so that one end of the (straight bar or mullen) mouthpiece touches the other. I would argue that it is, hands down, the softest bit out there.
The only problem with it is that the chew-ers can chew right through it (and so you need to be really wary of the brands that have a steel cord in the middle). KKs and all that are probably great, too, but why not try something that costs less the $15 first? In fact, just to try it, you can get one for as little as $5, brand new, from the Libertyville Catalog–the rings are just nickle plated, but it’ll last long enough for you to decide if that design works.
You know, it’s kind of funny how an utterly simple and amazingly inexpensive potential solution–one that’s been around forever–hasn’t gotten much attention here!