You can feed them worms you find while plowing if your willing to chew them up first... This Limited Edition item was released for Easter 2010. It was available for 250 MC from March 30-April 8, 2010 and gave 1 xp when bought. This item was re-released from August 11-25, 2011. The description reads "They look hungry."
Clicking the nest causes the baby chicks to bounce up and down uncontrollably.