Genetics is always fun! This is for Buff African and Toulouse geese and Brown African and Toulouse geese.
Brown African gander X Buff African goose = ALL Brown offspring
Brown ganders carry buff genetically [call this B/B1]
Brown geese DO NOT carry buff genetically speaking
B/B1 gander X Buff African goose = 1/2 males AND 1/2 females Brown
and 1/2 males AND 1/2 females Buff
B/B1 gander X pure Brown female = All males Brown
1/2 females Brown AND 1/2 females Buff
Buff gander X pure Brown female = All ganders Brown [this is B/B1]
=All geese Buff
(Also works for Dewlap Toulouse).
I have 2 buff African ganders with a buff female and 2 Brown African females meaning any brown goslings that hatch in the incubator will be male.