I've been following with interest the work some of our fellow bloggers are doing with their horses in bitless bridles - if you would like, identify yourselves and mention the bitless you're using in the comments so people can look you up. A lot of people seem to find the Dr. Cook's particularly good - I like the way it applies distributed pressure on the poll and cheek as well as the nose. I've used other bitless bridles - there's an English one around with rings on the noseband and of course there are sidepulls and bosals. I'd describe the action of the Dr. Cook's as closest to the sidepull, but I like the addition of the cheek and poll pressure - I'm thinking this might improve the horse's relaxation.
Now I'm not against bits, properly used, and will likely continue to use them. But I also don't believe that a horse can only learn to be soft through the head, neck and whole body by using a bit. Bits are just traditional in certain disciplines, but that doesn't mean that they're inherently better or worse. I've seen beautiful self-carriage and softness in horses that were ridden in sidepulls and bosals, and in horses ridden in bits. All the bit or the bitless is, is a communication device with the horse. A bit, or bitless for that matter - some bitless options can apply painful pressure - used as a control device isn't about softness.
So Maisie and I ground drove a little in the Dr. Cook's - that was just fine. I had somewhat more ability to be subtle with my cues than when ground driving in the halter. Dawn and I also tried it - just by chance, as with the saddle, she and Maisie wear the bridle on the same adjustments. Dawn and I just did a little lateral flexion and softening work in hand - she was very responsive to it. I'm thinking that with Dawn, the bitless may help her to relax and worry less - we'll see.