I know, but most medicated starters have instructions to feed to chicks as their sole feed until 7 or 8 weeks of age. So the manufacturer may be trying to make things seem more straight forward, simple, and consistent by marking medicated starter as "food for poultry less than 7 weeks" and all-flock as "food for poultry over 7 weeks." It is an arbitrary distinction of course and largely unnecessary but that may be their reasoning.It's not just one brand there are a lot of "all flock" types that say this.