Please update us on them and let us know the outcome.
Vitamin E can also be an issue with various leg and foot issues as well.
I'm wondering what they are doing with the organic feed that is causing problems? It could be as simple as seasonally different crops with varying nutrient profiles, crops coming from different farms, poor vitamin/mineral mix, going rancid from sitting in warehouses/stores too long, etc. I don't think it is good for any birds to be fed straight "chicken feed" with no other variety so perhaps some of the problems folks are having could be that they are restricting to only what comes out of the bag?
We've never fed soy since beginning with chickens but I am also using fresh grains and grinding myself at this point. (When I started the feed mill did a mix for me that I shared with someone as they required 300 lb minimum). (When I mix my feed, I always use Fertrell Poultry Nutribalancer for the vitamin/mineral mix in it. One of their formulas is made for organic and is not synthetic.) The babies get the exact same feed except ground smaller.
Last year I started an experiment. I decided to stop using legume seeds altogether in the feed. (I was originally using field peas but, seriously, they almost always left those and when given a choice would not eat them in any form - even sprouted.)
To compensate for that protein loss I have been using a higher percentage of sunflower seeds. So far they appear to be doing well on this. Of course there is an upper level of percentage of sunflower seed that you can use in the total feed so I am mindful of that. And I don't know that this will be my final feed formula. We shall see. I guess it may not be a great experiment, however, as my birds get other things than just what's in the feed. Adults free-range and everyone gets some brewers yeast from time to time (more often for the babies), various raw meats from time to time (more often for the babies), home-made kefir or yogurt from raw milk when we have extra, etc.