This is how I think of the hets and percentages.

A 100% het for Pied means that one parent WAS pied and one was not. Each and every baby absolutely carries the pied gene.

A 66% het pied is a little trickier. It means both parents were het pied, but because neither was a visual the odds change. For example, in a clutch of four eggs, statistically you will hatch one pied, two hets, and one non het. The trouble of course is that the het cannot be visually separated from the non hets. So you call those three babies 66% het, since statistically you have a two in three shot at the het.

A 50% het pied means one parent was het, one was not. This means in a four egg clutch, statistically two babies are het and two are not. But again, you can't tell them apart visually, so you say they are 50% het. There is a one in two shot at the het.

Each time you breed a het to a non het, the chances of hitting the het go down, and thus the percentages do as well.

If you bred a 50% het pied to a non het, then it drops to a 25% chance of hitting the het. And so on.

Gale