Sprouting the barley is going to decrease the anti-nutrients and make it more digestible. Are your turkeys getting 5 TBSP EACH per day? How much of their total diet does the barley consist of?
My birds are getting barley sprouts on a daily basis. (with occasional sunflower and millet sprouts) For 30 birds, they are getting about 6 cups of sprouts per day. I'm not letting it go to the fodder stage.
I'm assuming that your turkeys are a year older! that could be affecting their laying. This is an off year for my chicken flock also, partially based on the fact that I did not start their supplemental light as soon, and I'm also laying a lot of the blame to the miserably cold weather we've been having.