Who old do my chickens need to be to get the chicken finisher?

[tuckeb2]

I need to know how Old my chickens need to be to be put on the chicken finisher feed ? they have gotten their combs and they are 13 weeks old now? Can someone help me please.

 

[Mountain Peeps]

This is a link I've made. Hope it helps!

https://www.backyardchickens.com/a/feeding-at-different-ages