Where is Queen Liz?

Checked a small hive today for the sixth time and still haven't seen Liz! Plenty of eggs, 3 or 4 frames laid recently so there is obviously a queen in there somewhere. Can see the queen in all my other hives. Has anybody else had this problem? As I am heading for my first winter with bee hives, has anyone any tips for how much honey stores the bees need to safely overwinter?