I believe the EU requirements are minimum space (6 hens/sq. meter, not exactly running space), and organic feed, which is basically no GMO, no synthetic fertilizers/pesticides. grain-fed labeling is only compulsory if you label as such. Fish flour feed, if it's from fisheries, is allowed, since it's from wild origin.

I used to be a partner at a company the produced BIO produce. The things we were allowed to do within EU rules would surprise most consumers. Things like using copper sulfate, and other "natural" pesticides without limits, phosphate and other fertilizers which are not synthetic, greenhouses with artificial lighting, etc.

From your user name I'm going to assume that you are a Finn. It's possible that Finland has stricter rules for BIO/organic (good), but EU regulations are way less strict than what people assume. People see the BIO/organic label and assume that grandma was hand feeding the hens from her apron.