My boys both loved phoenix worms. They are all they are cracked up to be. When you order them or pick them up at a pet store they are in some type of bedding. You can leave them there if you want but I take mine out and put them in a critter keeper with over-ripe fruit/greens. They devour this stuff and grow to at least an inch in length and 1/4 inch wide! To separate them from the fruit mess I just scoop some of it out of the container, plop it into a bowl and add warm water. The maggots float to the top where I scoop them out into the boys serving dishes. The warm water makes them very active and attracts the cham's attention. I get 300 at a time for just under $21 (including shipping) from rainbowmealworns on ebay. They have the best quality worms by far, they are great to deal with and if there has ever been a problem they work hard to make it right.
By the way you can still feed the dark ones to your cham. The darker ones are close to pupating but if they still move once they are warmed up I feed them off. If they are not I just toss them into the bottom of the cage to let them complete their lifecycle and the flies hatch out in the cage. If any do escape they are easier to catch than houseflies. Actually they are very good composters if anyone is in to that. There is quite a bit of information on how to do that on the source of all knowledge (AKA the internet).