Here's my cages - they are 3' deep and in about 5' depth and staked/tied to both shorelines in order to ensure they have 2' beneath them which I was directed was important for caged spawning YP.
How to feed? I was throwing AM but only 10% was making it in the cage - and on windy days I had to abandon feeding altogether. So per Scott's suggestion I rigged a very primitive, but so far effective, feeding tool.
Allows me just enough reach [20'] to slowly sprinkle AM 400 and keep them fed and hopefully in the mood.