LOL Maddie, don't worry about keeping enough weight on her, just show her a pail of oats and she will put on several pounds
Just keep doing what ever you are doing with her, but remember she will pack it on in style when the spring grass comes through if she is grazing the whole time.
If she is out 24/7 I would seriously think about having a muzzle on hand, just in case, so you can limit her grazing if needed.
Remember to if you start riding her a lot more she will burn calories, the trick is to remember to feed after the event, not in anticipation of it...especially with Haflingers.
I would be very interested to see pics of her when she sheds out, he body condition looks so like Fancy's I just want to see if they are the same when you can actually see them. I just so excited that I can feel her ribs this year, it is a rare event around here.