I have 10 eggs incubating under a heat lamp. 6 days ago we could hear them scratching and pecking in 3 of the eggs. The next 2 days we could really hear them. Then 2 days ago we only heard a few pecks, we checked them all day, we figured they were tired. Today we couldn't hear anything. Not even a single peck. Are the ducks resting? Could it be too hot? We took the cover off the box today.