Good, the breeder was probably knowing how to handle such foals.
It is always good to be forewarned and go into this with a plan in mind and asking questions, as you are.
If she lost her mother at one day old, your vet will tell you how to handle her best as far as vaccinations, since she may not have had enough maternal immunity to help build her own immune system the easy way.
He may want to work on a different vaccination protocol than if it was a naturally raised foal in that respect.
We had one mare die and the foal was barely 3 weeks old, that we had to raise on a bottle and then transferred to nursing from a milk goat up on a bale of straw.
We kept her with an old mare and then at five months weaned her with the other foals.
Even then, she was a bit different than others as she was very, very quiet and secure, nothing bothered her, but if something did, unlike the others, she may plow right thru you like you were not there.
We had to work on that for a while, but she did come out of it and when we sold her as a two year old she was fine and went on to run like any other race horse, they told us.
She happen to be one of our last foals, before we quit breeding and running, decades ago now, that is why we didn’t go on to train and race her ourselves.
That was her, the bay in the upper left: