How old is too old to boil an egg?

[estpr13]

I did a search of old eggs, boiled eggs and floaters but couldn't find anything about this.

I have some eggs that now float when put in water. I've been told that they are too old to cook. But they boiled up fine. other than being a bit rubbery.

Are floaters safe to eat and can I mash them up and feed them to my chickens? Some of the boiled egg posts seem to indicate that old eggs are okay to boil.

 

[Ottoman]

You know, it’s not by accident that our nose is right above our mouth. And eggs are one of those things that when there bad you know it.