Why do we say "per egg" instead of "per clutch"

[purplemuffin]

Compare it to flipping a coin. If I flipped heads 10 times in a row that has no effect on the 11th flip. The 11th flip is still a 50/50 shot.

So, if you have a six egg clutch from lesser x normal you would expect three lessers and three normals; however, if the first three are lessers you still have 50/50 odds on the last three eggs.

That's a much better way of explaining it, I couldn't figure out the words to use.