I have been feeding primarily BBS, and I supplement feedings with a mixture of boiled egg yolk and liquidated bloodworms that I sometimes pour a few drops in while they are feeding on BBS.

The egg/worm mixture actually helped me with 2 albinos I am also raising when I had a bad batch of BBS eggs. They lived well off of it for nearly 5 days until I could get a decent batch going. The albinos are now forming their front legs and doing well