Rob, I don't think protein is the issue either for fertility. I have been feeding my birds 21% protein. I have recently changed their feed (FRM Show Gold Trio) from the grower which is 21% to the maintenance which is 12½ %, mainly because I don't think they need the extra protein during the hot months here and I had talked to Matt's dad and he told me they switch from the grower to the maintenance after the breeding season until late summer months when the birds start their molts.The only real issue I had was with my RC RIR male. He is one year old this month. My other males seem to be doing the job especially my Reese males.Not only the balancing act of a young male it is also the female submitting correctly. If you up your protein that might help. I know that in one breed I have I have to use a higher protein to get good fertility.
Alieda