Thanks for pointing this out to us, Epicgamer2592. Our developer thought this was fixed, and is trying to figure out why it's still broken. We'll have an update out to (hopefully) fix this once and for all.
If possible, would you be able to elaborate on what glitched with the Duck O' XP?
We've got an update in progress that will alleviate the issue with having 2000 ducks and individually upgrading them. We're also looking into what may be wrong with the Maximum Science achievement, to see what may be wrong.
Currently, the 'XP Bread' doubles the digits, that's why it goes so high in nubmers.
The game logic is that the duck levels up after it reaches 00:00 seconds. When you feed it another type of bread, it goes to 00 and the duck levels up.
One solution might be to give the 'XP Bread' the ability to reduce the remaining time.