Parashas Kedoshim · Passuk 19:05
Chabad.org — English translation + Rashi
Torah Temimah · Menachos 29a · Rav Yosef.
English: “You shall slaughter it” (singular) — teaches that one person may not slaughter two sacrifices at once.
One shechitah per act for kodashim
The singular form limits the act: kodashim are not slaughtered two-at-a-time in a single stroke the way some hold for chullin.