http://www.ehow.com/list_7258154_foods-high-estrogen.html I sure have not found any feed that is 100% soy so they are not getting high levels of soy and you might want to read the other food that have estrogen including grains. HMMM
While soy might not be the main ingredient, anything adds up over time if its a regular part of the diet.
It's even recommended that humans don't eat soy more than 3 times a week.
I simply feel there is enough evidents for concern regarding soy as well as GMO grain products used in most commerical feeds.
If you don't agree GVF well then we'll just have to agree to disagree.
I'm sure as time goes by we'll all know what the fall out from soy and GMO is or isn't.