Putting weight on pregnant mare?

Ok we got our new (very pregnant) Appy mare yesterday, and I'm REALLY dissappointed. She is far thinner than I would have expected and much more "beat up" based on the fact she came from a "reputable" "show" person in the midwest. (She hasn't heard the last from me yet)

So she needs weight (her hip bones are showing , AND she has something going on with the backs of her feet. Her hooves are in bad condition (pretty chipped), but some of that may be from stomping flies? The bigger issue are the sores she has on the back sides of her feet between the ankle joint and the bottom of the hoof. Is this Maybe something fungal? I've called the vet out for a health check on her today, but wondered if anyone had any insignts on how best to put weight on (she's due to foal mid August) and with the feet thing.

Oh geeze poor guy!! So hopefully she's showing signs of going into heat??
I'm having unexpected major surgery Monday and won't get out of the hospital until Wed the earliest, so hopefully she will be finished and we can get her this weekend?
Re the new mare, she's not emaciated, but I can see her hip bones, and the outline of her ribs, much thinner than i would like. Luckily, she's a good eater, so i'm feeding her twice a day on Nutrena, mare/foal vitamins and soaked beet pulp along with lots of free choice hay. Her temperament is awesome. The baby should be leopard or near leopard. She's had 3 previous leopard babies and is bred to a few spot stallion. She's a reverse leopard herself with a blanket.
Thanks for taking such good care of Rage I mean Sage....