Must be claw damage instead of spur then. And they'd still have cockerels if under a year.I have 6 roos but none of there spurs are sharp yet. I've tried hen saddles before and they didn't work out very good they made the roosters rape the poor hen even more. I have 14 hens and am probably gonna get 3-6 more this year. The best behaved one is usually the one who is lowest on the pecking order.
Try the double strap design? Better then the single.
I think in your case here, you have to down size the boy group.
I don't have this problem, & I keep lots of roosters.