I had Fantails myself while ago, and I understand that they are NOT good parents. They have no instinct on how to care for a baby. You, can let the baby hatch, wait a few days, and then start handfeeding it. I suggest that you go to a pet store, and they will teach you how to properly hand feed a baby. Get Kaytee Exact baby bird formula and find a good eye dropper that has a small tip. The formula must be 105 degrees to 110 degrees. If you go any higher, it will get crop burn, which is fatale to a young bird. Buy a critter cage, (Container) use a heating pad, and make sure it’s nice and warm. Maybe 80 degrees. I wish you the best of luck.
TBird

You can tell what eggs are fertile by shining a light through it, if you see veins and a dark spot, it’s fertile, if you see nothing, it’s not. And baby birds are not hard to care for, as long as you have the time, b/c baby birds need to eat at least every two hours. I had a baby mocking bird I hand raised after a storm ripped it’s nest out of a tree, killing it’s other siblings, and it was very fun, and I learned quite a bit in the process. I let it go when it learned how to fly, and it reunited with it’s mom, and it’s mom was actually feeding it! I was surprised since it was imprinted on me, b/c I found it before it had opened it’s eyes. I was thankful, b/c I didn’t know how to teach it to feed itself. Anyway, I would definitely go for the hand rearing, it’ll bond you with your bird, and if you take it before it opens it’s eyes, it will think you are its mom.