If the eggs are freezing, I honestly don't know of their chances, but I would assume that it damages them beyond repair. In non-fertile eggs, the only reason for "blood" inside would be a blood spot, which generally happens when a small piece of the hen's reproductive tract sloughs off and ends up inside the egg. (Yep, gross, especially if anyone didn't know that before.) You will only start to notice the yolk becoming vascularized when the eggs are being incubated. The difference between a blood spot and egg vascularization is so different that you shouldn't have a problem distinguishing whether or not the egg is developing. There is really no way to tell if a day one egg is fertile to the best of my knowledge. Once it has begun incubation, you will actually notice full on veins going to a certain part of the yolk. These veins will get larger as the days progress and you will see them heading to what becomes a very obvious embryo by around day 3 (I believe). Once they have begun to develop, they're very fragile, and die quite easily.

Hope this helps, btw, I'm an Animal Science Major at UConn and I have a pretty large amount of experience with horses, I saw that you were asking someone about training advice. Feel free to contact me.