Browns are piscivorous. Whenever I catch one, I expect it to cough up a smaller fish or two, even if the trout is only 10-12".
They are aggressive feeders and I will always use a full nightcrawler if I have the option. Smaller pieces may work fine, but I try to refrain from catching the very small trout, and small trout have an easier time grabbing a small piece of worm. You may have trouble getting a small piece of worm to sink to the bottom of the stream, where browns are most likely to hold. By the time it reaches bottom, a feisty baby trout may nab it.
Corn would be my last choice, though I'm sure it could work. Nightcrawlers are free and easy to gather, as are other insects for topwater action. Crickets, beetles, etc. Mepps and Panther Martin spinners work great too.