one of every four eggs.. since mojave are het leucy.. each parent has a 50% chance of throwing the mojave gene.. so 25% are normal, 50% are mojave, and 25% are leucy.
If you assume you have N eggs hatch from a clutch then your percent chance of producing a Lucy is (1-.75^N)*100
1 egg gives 25% chance
2 eggs give 46.8% chance
4 eggs give 68.4% chance
6 eggs give 82.2% chance
8 eggs give 90% chance
an infinite amount of eggs produces a Lucy with 100% chance