Why would eggs have blue in them?
With boiled eggs, the yolk can get a blue/green tint, particularly when over-cooked or cooked at too high a temp a reaction most of us have seen.  It is a reaction between sulfur and iron.  The same can occur with scrambled eggs.  Over cooking and cooking at high temperature is considered a prime culprit.  Cooking in iron reportedly increases the likelihood as it increases the available iron for the reaction.  If the eggs are old, or if the birds have had a diet that resulted in a bit more sulfur in the yolk it might be more likely.