I remember reading somewhere in the core rulebook how many fate points NPCs ought to have in an encounter, but I can't find it now.
So, where can I see how many fate points I should give my NPCs?
You can find those rules in the Aspects & Fate Points chapter, under The Fate Point Economy. Page 82 of the book mentions the GM and Fate Points. You can read it here on the Fate SRD.
In short: the GM starts with one fate point per PC in the encounter. As the GM, all your NPCs collectively tap into that (small) fate point pool.