First let’s consider the odds that you have a double het among your four possible double het girls. Each of the 4 girls has a 50% chance of being het albino and a separate 50% chance of being het axanthic for a combined 25% (1/2 X 1/2 = 1/4) chance of being a double het. Another way of saying that is it has a 3/4 chance of not being a double het. The combined chance of all four not being double hets is (3/4)^4 = 81/256. The chance of AT LEAST ONE (or more) being a double het is 100% minus the chance that all four aren't double hets so 175/256 or about 68%. So the odds that you have at least one double het in the four possible double hets are better than 2 to 1.

So "all" you need to do is get all 4 to breed and produce enough eggs to hit the 1 in 16 odds to get a snow from any females that are double hets. We can do a similar calculation for the odds of producing at least one snow from a pair of double hets. Once you hit the odds above and are actually breeding a pair of double hets each baby has a 25% chance of being a visual albino and a 25% chance of being a visual axanthic for a combined 1/4 X 1/4 = 1/16 chance of being a snow. Your odds of hitting snow go up with the number of eggs you hatch (just like your odds of having a double het went up with the number of possible double hets you raised up). Each egg has a 15/16 chance of not being a snow. The formula for your chance of getting one or more snow from a random group of eggs from a pair of double hets is 1 - (15/16)^n where n is the number of eggs. It works out that with 6 eggs your chance of getting one or more snows is almost 1 in 3. But if you could get 12 eggs (perhaps in two years) your odds go up to about 54% so more likely to get at least one than not. Once you get up to 24 eggs your odds are nearly 79%.

So, a lot of work and a lot of baby ball pythons but heck, we all like those anyway.