Marcy, if it were me? I re-vamp the diet for a month. Forget the Red Cell and the other base feed and feed something else. Are you certified organic? Is this a requirement for your program and integral to your project? If so, then go get something else, anything else, that is organic and has 20% protein in a fully balanced feed.
If not, then let us know what feeds your local feed mill supplies and maybe we can suggest something. It is urgent for you to get to the bottom of this ASAP and by golly, I'd want to know quick and I'm sure you would as well.
Cold turkey. Complete change in feed. Stay on the new program for the next month. Within 3 weeks you'd know if something was amiss in your previous diet. If nothing changes within a month, then alert Houston that you've got a problem.
I don't think it is the feed. Rhode Island Reds, Orloffs, and Buff Rocks on same diet have good fertility. In fact, fertility on the Buff Rocks (2 pullets in with one cockerel) is almost 100%. The organic is integral to my program, yes, of not feeding GMOs and not supporting Monsanto...