66% Hets means that .....each animal has a 66% chance of being het pied and a 33% chance of being completely normal. If you got a male homozygous pied and bred it to a normal female you would get 100% hets. If you breed a 66% het pied to a normal female you may get normals...you may get het pieds...it all depends on if you 66% het pied male is het pied or normal. You need to breed two 100% het pieds together to get a homo. pied.