Heh heh,
Wait till you are breeding them.
I started staggering my feedings years ago - hardly ever have to waste food anymore.
If you have 10 to feed but suspect 3 may not eat then only defrost 7 and offer to the possible non-eaters first from least likely to eat to most likely.
Then if they all stun you by eating defrost some for the three you were sure would feed no problems the day before.
Important note Do not do this between animals in your main collection and those in quarantine.
Saved me a fortune in food.
dr del