Sam the Man and the Chicken Plan by Frances O'Roark Dowell illustrated by Amy June Bates*

My eight year old read this book to himself and then gave it to me to read.
Second grader, Sam, wants to earn $20 a pop like his older sister Annabelle does when she mows the neighborhood's lawns.  When she is too busy to take care of Mrs. Kerner's chickens, Sam volunteers.  When his classmates share special objects for show -n -tell, Sam realizes he is not an expert on anything like they are.  He decides he wants to be a chicken expert.  Now he just needs a chicken!
Perfect series for transitional readers.
*Highly recommend.
-Borrowed from the library.