Due to my horrible luck with life I kinda wondered. If I have 2 bde's and both fail, then next day I hatch 2 more, does that count as 4/10 or 2/10 and 2/10? I've hatched so many eggs of all sorts and all have failed but only 2 or 3 at a time. Would I have a better chance of getting 10 then try to hatch them all?
You can't really add 2/10 + 2/10 = 4/10
If you could do that, that means after 5 days (10/10) you will be guaranteed
to have a Baby Demon.. which is not true.
10% chance means that on average
1 out of 10 eggs will successfully hatch.
Some players will get it on their first egg, other unlucky players will get their Baby Demon after 20 eggs.
So yeah, there isn't a real answer to this.
As for myself, I usually buy a bunch of eggs, drag them into one of my hotkeys and them spam
that button until all the eggs are opened or a pet has hatched