Hebrew National hot dogs come seven to a package because meat has traditionally been sold by weight, specifically by the pound, not by a numerical count. The Hebrew National package of seven hot dogs weighs one pound.
Other Hebrew National products are also sold in packages that weigh one pound. Its "bun-length" hot dogs, which are a little longer than the standard ones, come in a package of six. Its quarter-pound hot dogs come, not surprisingly, in a package of four. Many other brands of hot dogs come eight or ten to a pound. Hebrew National sells all-beef hot dogs which it markets as kosher; however, not all kosher-certifying authorities agree with this assessment.