A small amount of money; peanuts, small potatoes: Two million? That's chicken feed in this milieu(1830s+)
The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D. Copyright (C) 2007 by HarperCollins Publishers. Cite This Source
Idioms and Phrases with chicken feed
Trifling amount of money, as in I'm not going to mow lawns for $5 an hour—that's chicken feed. This expression alludes to the fact that chickens can be fed corn and wheat grains too small for other uses.
[ ; early 1800s