Thanks for all the info! I read that stress can cause ridging in the hoof, and she definitely had stress with the move to my place this year. She also went from dry lot to grass. I was careful about the transition, checked her feet twice a day and had her in a grazing muzzle. I had visited the safegrass site before, too, so I'm irritated with myself for not being aware LGL could happen.
I'm going to put her on a 4 week trim schedule and discuss hoof supplements with my farrier. When I thought about it I realized that hoof has always been prone to cracks since I've had her (5 years) but they've not been as pronounced b/c she's always had shoes. So we may need to put shoes on the front. I'm also going to examine her diet more closely.