I give my hissers stuff from right out my garden , and fruit that I dont completely finish. they eat everything and anything I have ever offered, and no die off from the garden food, or grocery food. I even have fed them raw dandilion greens. they are garbage disposals. for a treat I give them chiclid sticks or other fishfood.
only deaths I have had have been from old age, or a horrible molt gone wrong.
isnt it interesting, yours are dying and I feed mine without a care darn near anything I would compost or whatever, and my colonly could care less...
there has to be other food or envrionmental issues at play when ppl mostly feed the same and one guys colony suffers while another thrives.
dude I have cleaned out my jucier after a ginger carrot and kale drink was made, and squished the waste into a ball and dropped it in the colony and they devoured it without any ill effects... gave the same food ball to my dubia and they loved it as well.
I dunno.