What causes yolk/liquid to turn green/blue/gray in hatching eggs?

[speckledhen]

Had this happen to a friend. Turned out to be an ecoli contamination due to bacteria in the nests getting into the eggs pores (not her nests, the breeder's), then add heat and humidity and presto! Instant bacteria contamination.

 

[Wynette]

Hey, Cyn - thanks for weighing in - I always appreciate your opinions!

How did they confirm an e-coli bacterial contamination issue?

 

[speckledhen]

They had a chick necropsied.

 

[Wynette]

Ah...okay. Gosh, I'll have to research to find out what the signs are of e-coli. None of my chooks are ill, but maybe it's not the type of thing that displays with symptoms. My eggs are usually very clean...but I suppose it could have been caused by a dirty egg...gosh, there's SO much to worry about with hatching eggs!