Flexion

At my barn, a 3 year old Percheron/Thouroughbred mare, Jazz, is getting introduced to riding. I've been working with her since she was 6 months old and abandoned at an auction. As far as I can see, she is such a sweet girl and naturally talented in dressage. One thing that I am worried might make things harder for her is her neck. Being half Percheron, her neck is a little short. Are there any ground excerisizes or anything I can do so she can flex it easier as she moves on her dressage career?
Thanks, Claire.

what I love to do with my horse, is I'll warm him up normally, then do circles, make him bend in both directions. Weave in and out of cones set up (not tight turns, just enough where he has to bend to go on the other side of the cone). I'll also make him stand, and I'll stretch his neck to each side.
After I do that he collects himself alot better.

He's not half draft, nor does he have a short neck, so it might not work for her...but just thought it might help a little bit

Have you ever practiced the carrot streches?

There's a picture. It's simple, easy and helps. Grab a carrot or two, and bend her to both directions, like the picture is showing. Don't overbend her, though.
I'm not 100% what her problem is, though. Is it because she doesn't have training, or is it because she's stiff?

Serpentines.

There's a great video on here, by one of our members. She shows you how to teach the horse to go into a headset using serpentines. It's a great video!
http://www.horseforum.com/viewtopic.php?t=7552