I purchased 20 crickets from the pet store and I am keeping them as pets, not for food.?

[Mister Bates]

What should I feed them, please? I've had them for two weeks and have been feeding them dog kibble soaked in water and apple/ potato / lettuce.
Thank you Sasha, but that food has added calcium and is for herp health, nut not so good for the crickies.