Day 10: it’s a bantam chick- I mean I know it’s hard to say for sure without looking at it through your eyes… but it doesn’t look like any of my others
I’d guess it is an early embryonic death, died a couple days ago, starting to clump up, if the liquid is really sloshy, that would be another clue, eggs should ooze like honey not water. Don’t be afraid to open it and see what it really is, best way to improve your candling.