That red line should be straight -- not angled. It's telling you that your horse is trying really hard to grow hoof wall and put his frog on the ground, but since the shoes are there the walls are pushing up on the soft tissue as the frog is desperately trying to push down. I can't seem to word this properly, but your horse wants to do all the right things and the shoes are preventing it.
So, loose the shoes, the walls can grow back healthy and be trimmed with proper angles, lower and backed heels, while the frog can make contact with the ground and spread and grow out. I think your girl would turn around pretty fast with proper care.
Beside is a great pic of what it should look like:
Last edited by NorthernMama; 05-25-2009 at 05:57 PM.
Reason: edited because it was unclear