So, since little Miracle has come I noticed a few things. She wouldn't graze much, was hesitant to take treats, and pawed almost violently when I would bring her in to eat.

This evening I took a look at her little teeth and was horrified at what I saw. One bottom front tooth was completely broken off at the gum line and the opposite top front tooth is horribly fractured all the way across. The owner told me that she was getting beaten up pretty bad at the barn he had her at... She has obviously been kicked in the mouth.

Sounds like you're going to have to have a visit from a equine dentist ASAP to take care of this.  Or if you're are near a vet school and the owner can afford it, they may be able to help her.  In the meantime, you will want to feed her stuff that she doesn't have to chew much.  Wet down her feed really good.  Grain, should be soaked for a couple of hours so that it softens up for easy chewing.  Pellets also break down when wet for easy eating.  Soaked beet pulp is good for putting on weight and easy to chew.

Good luck.

Spotted Pony

Sounds like no matter what this mare will never be able to hold weight on a short pasture.....  :(

Where are you located?  You need a good equine dentist.  There is a school in Idaho that specializes in difficult cases that might be able to refer you to one.  These people have helped horses and mules worldwide that have teeth problems.  The problem with teeth is that the molars continually grow, and the whole mouth is affected by broken teeth (incisors included).  This means she needs her mouth balanced ASAP.  I have horses with broken molars, and we have to rebalance every 4 months because of the way the molars grow.  I'm not sure about all that can be done with incisors, but they can do things to balance the mouth to allow chewing/grinding. 

Equine dentist ASAP.  My older gelding (now gone) got kicked in the mouth before I bought him and no one caught it before (of course) I bought him.  He lost all of his incisors to the dentist, had to be feed squishy food (technical term) until the gums healed.  But he was able to graze and eat normally within a month.  I was amazed!  They really only use the incisors for tearing the grass (and each other! lol!) and his gums and lips were sufficient for him to graze!  He may not have gotten as much grass but he seemed happy and healthy and in a lot less pain, and lived several more years before dying of cancer!