I had 5 duck eggs under our chickens. One hatched, One kinda hatched and I found it the next morning (looks like mom kicked it out of nest) and now...a week later, surogate Mom is not sitting on them and they have large purple coloring on the bottem of them.The eggs are Rouen"s and are normally green. Put them under chicken because momma duck was not interested. Are my eggs done ??? Don't want to throw them away just in case. Now.... momma duck is ready to sit on them ( five weeks later). She commandered our chickens nest and is sitting on non fertilized chicken eggs. I shoved the remaining duck eggs under her. How long should I wait until I toss them ? The eggs are about 6 weeks old. It is the purple coloring that has me worried.