On the other clutch I seen what looked like a dark bottom and an air pocket. But I don't think what was inside survived, I to am going to wait an additional 4 days to make sure.
I do know with canary eggs. If you candle them with a flash light small enough or an led light. if it is not fertile it will be clear and light up like a light bulb that is colored. the light will flow through the egg evenly, and you may see a small speckle of where the yoke is. I know about the unfertile part from the last 5 years when they laid eggs but weren't in pairs. they were separated.
This is my first attempt at pairing and breeding, and from what I have researched, and was told from others there are many stages. from procreation, to incubation to hatching. Incubation being the longest and hardest to determine. Some eggs may have been fertile and shown signs of fertility but may have died in the process of being incubated.
As far as it being to early that can be another issue. I wouldn't give up just yet. it just means the hen or the male was not ready to mate yet. Chances are their second clutch will come out better because its more in season.
It is always sad to see they are not fertile and viable eggs, I think we take it more emotionally then the birds do.... lol This being a hobby I was just excited to have just 1 hatch, it made me a proud breeder that I am in the right direction to doing something right. We learn from our mistakes and or add to our personal experiences and knowledge and pass it along.
Please keep me posted, I take stories and advice to heart and mix it with my own. its always good to hear what worked and didn't work with others.
I don't have a specialty with becoming a breeder, but I am more fond of breeding crested canaries. they catch my eye the most. Problem is they are more of an advanced species, than a regular song canary. One thing I do know is cant breed crested with crested cause there is a 75 % to 100% chance that all babies will be born dead

My first hatchling was with a dominant white hen and a crested fancy.
Hope to hear how your next few days work out for you. and the suggested incubation is 14 days but some eggs take 16 days depending on when the hen starts the full incubation period.