Your having a yolk

Since K threatened the quails with going in the pan if they dont lay any eggs. They have been laying every day!
A friend of ours offered to lend us her incubator but we needed to see if the eggs were fertilised. She said break one and check to see if the yolk has a white dot in it. ( you learn something new everyday)
So thats what we did. And yes it does!
Incubator warmed up ready ...but they havent laid today...... Maybe another threat might help!