It makes zero sense for companies to be required to list what is NOT in their food. Yeah, let's scrap listing ingredients and instead list everything that isn't in an item. ;)
Edit: (sorry for changing my comment, I add the original below).
You are picking on the wording. There must be a succinct way to say non-genetically modified animal.
If it's GMO: GMO-Chicken. Seems succinct as well.
Non-GMO Chicken. Least succinct of the 3.