I prefer to randomly feed them. Before i used to feed them on a schedule and i would have some uneaten crix. What i do know is
1. Get my pay check
2. buy a whole bunch of crix.
3. Feed my most important animal first. (the ones that need to be fed)
4. Feed of what ever crix I have left to whatever scorpion I didn't feed last week. (actually i get payed every 2 weeks but buy crix daily)
I switched over to roaches but Im letting them multiply right now so this is the way it goes. Sometimes i'll feed them about 2-3 crix then feed them in another 2 weeks or in another 2 days. They eat all the time now.
I think randomly is the best to go. I usually toss a few in and let nature take it's course. Sometimes she won't touch a one, other times she'll chase the little buggers the moment they come near her burrow. I'll just watch to see when she's sitting at the entrance to her burrow with her claws up and open, kinda like, "C'mon food!!". Then I'll toss a few more in for her. Unless there's already a few in there, inwhich case, I just give them a friendly nudge to their doom.
I basically just see if mine are hungry or not ::shrugs:: If I use tongs and place a cricket or mealworm by them, and they don't pounce on it, I remove it. I check twice daily. So far, it seems to be working; the underweight scorps I rescued usually want at least one food item daily, and the appropriate weight scorp eats 1-3 items 3-4 times per week. I know most people don't tong feed, but because of the condition these guys came in, I try to ensure that they definately get all of their food. Sometimes the crickets die in the cage before they find and eat them since my guys have decent sized enclosures and plenty of hiding spots.