New to hatching eggs-topsy help

[gamebirdguy88]

I am new to hatching and have searched page but cannot find answers. I bought some cotournix quail eggs. Being my first hatch, I wanted a cheap risk. Bought eggs for .25 cents apiece. Guy said he has one male to five females, which I know is not correct, but figured if I have a 50% hatch rate it would be worth it. Well out of 300 eggs, I had 55 hatch on days 17-18. Nice chicks, none have died so far. I float tested all the eggs after day 20, most were high floaters, 30-40% out of the water. I then broke open all unhatched eggs. 2 were partially developed, basically seeing a ball with black spots for eyes. 3 were mostly formed chicks. Every other egg was just a perfect yolk. No development. What may have been the cause of the eggs not developing? Thanks in advance, this is a great site.