There is a good article on fermented feed here on byc but I don't remember the name of the article. I'll try and find it.
I believe @DobieLover ferments her feed.
I do this during the summer using crumble feed and cold water. I offer it once a day, every 3rd day I add a probiotics and electrolytes to the mix.
I like the all in one electrolytes & probiotics by Rooster Booster.
I leave it out for about 2 hours. It is too hot here to leave it for very long...