At the beginning of the pandemic, house bound, I decided I wanted to try germinating apple seeds from fruits I had consumed. After a dormancy, one of the seeds actually sprouted and I was obsessed with caring for it. It got about 6 or 7 inches tall, was transplanted into a bigger pot, and moved outside where it continued to grow. One morning going out to my car, I saw that some creature had chewed through the base of the tree and just discarded it on the ground beside. Panicked, I put my sweet little friend in water, hoping to save it, but it was no use. I was so upset I couldn’t even move or empty the pot it had been in. As a matter of fact, I probably left it for a month. But then, the craziest thing happened: the root must have been very established, and the darn thing re-sprouted!! Not one, but TWO trees from that root. I call it my ‘Lazarus’ tree. But now what? Do I leave the twins conjoined? Should I prune one whole half of this little tree? I have it inside under a grow-light at the moment to protect from outside critters and the impending frost. I live in USDA hardiness zone 6b. Do I leave it under light or put it in my basement for dormancy?
Great story! And great name for an apple: Lazarus.
Since you have critters outside, I would leave both sprouts for now. Until it gets big enough to not be eaten by animals anymore (do you know what animal?), you have more chance with 2 spouts instead of just one.
I don't know what kind of apple you had, but most apple trees can survive hardiness zone 6b. So I don't think it needs to be inside for frost. But I understand that you are afraid that it will be damaged again by animals. So if you keep it indoors, you can use grow light until it loses it leaves. Without leaves it doesn't need light anymore of course.
I hope in some years you'll have good tasting "Lazarus" apples!