I typically feed a combination of ration balancer and senior feed. I can readily get senior, it's similar to growth and easy to digest; growth feeds are special order, so a hassle. I feed a regional feed, as it's in stock. If it were stocked, I'd feed Triple Crown, and still the senior over the growth, as it's lower carb.
We feed a regional senior feed as well. 14 percent protein. They get it for their first full year and if necessary into their 2nd. By the time they are into their 2nd year most are getting our locally grown orchard grass hay with a vitamin/mineral supplement.