Q? How do you know who is eating???

[GartersRock]

I feed mine separately (OK I cheat, my adult DK's eat perched in my hand)

We have a dozen "feeding boxes" and place the snakes in them one at a time with food.

That way I know who eats, and what...

Same here! Deli cups and feeding boxes so I can be sure they all eat. My litter of 29. I have to do it that way or some little ones might not get to eat.
But yeah. All my snakes get fed separately.