Most stores can order it if they carry the regular frozen brine shrimp. It's from the same supplier. It's a more specialize food that not all store can sell as easily as the regular size. Good Luck.
Where in centcal are you? I know both petsmart and petco in fresno area do NOT sell baby brine shrimp, only frozen adult brine shrimp. Only places I've found frozen baby brine are Whitie's Pets in Fresno and Seven Seas in Clovis
yeah I've tried petco on blackstone, and the petsmarts at shaw/clovis & herndon/willow. none of them carry it (or had it in stock over several trips I've taken there). That's what made me start hatching my own is how overpriced whitie's is at around $11/tray