Yeah, generally speaking the average individual won't notice a difference in their roosters... Most peoples roosters don't make it far enough to die of kidney failure, they are usually eaten by something or replaced before then, so the average experience here might not be reflective of your needs. Between that and the fact that every birds body is different and many roosters CAN live to be 10 or so on layer feed it can be hard to notice any substantial differences. I didn't notice anything out of the ordinary with my rooster on layer feed, then he got eaten by a raccoon so it didn't really matter if he was going to die in a year or two from kidney failure. :T It's hard to justify feeding a totally separate feed for a bird that has a real chance of not making it past their first 4 years either way.
But for a pet chicken, a bird you care for and keep safe, a bird that isn't going to be lost to predation, isn't replaced with a more fertile and young cock, a bird that could possibly warrant vet visits, etc... Absolutely layer feed can be a problem. The reality of the excess calcium is true. It exists in all sort of animals, and it's a serious problem in even mammals like rabbits. It shorten lifespans and causes kidney issues. So if you wanna keep this rooster as a pet, absolutely just go for an all-flock feed and separate out your oyster shell for the hens.
If you're keeping your rooster for breeding (where their fertility likely falls off at 4-5 years and need replacing anyhow), if you are expecting your rooster's life to be on the line for his hens in a predator-heavy environment, or if your flock is for eating, layer feed will serve your purposes just fine. If you want longevity, separate the feed.
But for a pet chicken, a bird you care for and keep safe, a bird that isn't going to be lost to predation, isn't replaced with a more fertile and young cock, a bird that could possibly warrant vet visits, etc... Absolutely layer feed can be a problem. The reality of the excess calcium is true. It exists in all sort of animals, and it's a serious problem in even mammals like rabbits. It shorten lifespans and causes kidney issues. So if you wanna keep this rooster as a pet, absolutely just go for an all-flock feed and separate out your oyster shell for the hens.
If you're keeping your rooster for breeding (where their fertility likely falls off at 4-5 years and need replacing anyhow), if you are expecting your rooster's life to be on the line for his hens in a predator-heavy environment, or if your flock is for eating, layer feed will serve your purposes just fine. If you want longevity, separate the feed.