Hmmm! I am not sure where we are going with this thread, and no one has picked it up. I haven't seen you posting lately, so I was wondering if you died or what?
Used to be most of the commercial egg production in Mexico was marketed under the "Mezquital de Oro" brand. I am not sure who the big operators are now. I haven't been back since 2004.
Things change and yet they stay the same. I suspect there is more to this post than what hit the screen; maybe a link to a newspaper article that was omitted.
Eggs in Mexico are a different story than those sold in the US. The yolks are bright orange. Here we see that as a result of free ranging and freshness. The store eggs in Mexico are probably just as old as those sold in the US, but they add marigold to the feed. It makes the yolks look like fresh eggs. It also gives the flesh of the bird a yellowish cast like unto chicken fat. They like them that way there.
They slaughtered millions of factory chickens because of avian flu, but as I recall, Mexico is the land of the feral chicken. I would be more concerned with the feral animals than the factory chickens.