I am almost certain it is 25% chance on each egg for an ivory. So statistically, if you get four eggs, you would get one ivory, but there are good odds and bad odds, hopefully you will get good odds.
Ball Pythons:
0.1.0 Bumble Bee- Schnapps
0.1.0 Pinstripe- Penny
0.1.0 Super Cinnamon- Cleo
0.1.0 Albino- Daiquiri
0.1.0 Low White Piebald- Hershey
1.0.0 Low White Piebald- Reese
1.0.0 Paradox Super Cinnamon- Dash
1.0.0 100% Het. Albino- Jester
1.0.0 50% Het. Albino Jake