Arrrgghh. Organic and free range eggs are more at risk of being contaminated with dioxins because of the land the chickens are allowed to roam on. That's the only kind of eggs I buy!
This issue has only arisen in Germany but it could happen anywhere. It's so annoying to try and do the right thing and then discover the new risks you're taking. I'm also buying only organic and free range chicken when I can in order to avoid supporting the horror of poultry factory farming.