It's a personal choice and personally, I don't think it's worth the extra money. Just go into any decent search engine and type in something like 'organic farming approved pesticides fungicides herbicides' for my major reason for why I don't think it's worthwhile. You also never know where some of the base foods used to make up any commercial chicken feed, whether organic or not, actually came from unless you had a direct hand in their procurement. An organic farm, well intentioned though its owners might be, could be located right next to highways with major, major traffic or not far from industrial sites. You can imagine how such locations might be subject to a dose of all kinds of noxious chemical fallout in addition to what's deliberately being put on the crops, but you'll never know about all those extra chemical residues because by and large they're simply not tested for...
But still, nothing wrong with choosing organic feed. Theoretically, it should be the healthier option. The only type I'd ever stay away from, because of the slightly 'scammy' taste it leaves in my mouth, is the sort that proudly proclaims itself all-grain, vegetable-only, animal protein free...that sort of thing. I'm suspicious of those feeds because their advertising suggests that chickens are vegetarians and are better off eating only vegetables. Which is completely contrary to the truth, which is that chickens are omnivores who do just fine and enjoy eating animal protein. (Like those juicy worms and crickets and the scraps off your steak bone!) I'm always put off by disingenuous and misleading advertising and fake claims about chickens and chicken feed rank right up there with me...
I've only fed regular commercial feed and the birds have done very well with long life spans (record's still 16 years!) and very few disease or other health issues. That's really your best 'test', in the end. How your stock does on the feed you use in the long run.