I usually fill up an 8 quart Fortiflex bucket of the wet feed each morning. In the spring/summer, I cut back a bit when they start leaving some by evening - they fill up on other stuff as they range during the day. Basically, if there is feed in the troughs at night, then I feed less the next...
I've got 50 chickens. I've been doing fermented feed for about 2 years now and I use a large rubber feed can. We just add more grains and water when it gets low. Stir with the shovel every morning before scooping out to feed.