Will wants to teach Lucy where food comes from. His plan to give her a "teachable" momentincludes buying her a chicken. And it's just in time, too: The other day she asked if bacon, lettuce and tomato all came from the same plant. "Wait, there's a trick for remembering this," Kenny chimes in. Maybe Kenny needs a chicken too.
Either way, he definitely buys one. So does Grant, which bums Kenny out because he's been feeling inferior to the big guy lately, the most recent incident coming after Grant schooled Kenny on the football field in front of Nathan. (At least Grant apologized: "I'm sorry I was so much bigger than you yesterday.") So Kenny makes sure he gets a hen that's aggressive and pushing Grant’s favorite chicken around at the store. Kenny relishes his chicken pushing its butt all over Grant's chicken - until Grant's chicken turns out to be a rooster. And he impregnates Kenny's chicken.
Craig's dating one of Brenda's doctor friends, and it's going well, because she wants Craig to meet her son. Craig’s not worried, because in his words, "Kids love me and I love them. In fact, I consider myself a connoisseur of children." Kenny reminds him to tone it down. "Easy buddy, that phrase is what lost you the Santa job at the mall." But this is no kid. Dr. Donna has a large 11-year-old man-child, and he spends the next few weeks beating Craig up and torturing him while his mom’s not around.
But soon he pushes Craig to his breaking point, and Craig calls Donna's kid a "gigantic, thoughtless, humongous, out-of-control giant boy" in front of her. If that didn't nail the coffin shut on that relationship, he definitely accomplishes it when he becomes a child-man and goes into full tantrum mode, flailing and falling and screaming.
Lucy loves her chicken. So much that when they find it needs a $700 surgery, she sees no reason they wouldn’t pay for it. Will tries to give her a different teachable moment by teaching her about death and even brings in a healthy ringer for the chicken, all to no avail. He springs for the surgery. Theresa has the good news on the teachable moment Will was after, because Will just learned that "When it comes down to it, you'll do anything to make your daughter happy." Which is all he’ll have, because the surgery means the chicken can't lay eggs anymore.
After some tense battles over parental responsibility, and whether or not to keep the egg, Kenny and Grant decide to raise the baby together. It's beautiful. (Not really.) Grant's also better than Kenny at making chicken noises, making chicken incubators, and crying at the birth of a baby chick. Not that anyone's surprised by that.