Physicist solves the problem of the infertile chickens

WARNING:      You will probably not find this funny unless you are a
              physicist or know physicists (especially a theoretical
              physicist)

     There's this chicken farmer who has a huge problem.  It seems
that he can not get his chickens to produce at ALL.  No matter what
he tries out of the Chicken Rancher magazine, his chickens don't
seem to be fertile at all.  He tries everything.  Finally, out of
desparation, he has heard about this great physicist at the state
university down the road who can solve any problem.
     So one day, the farmer packs up a couple of his chickens and
travels down to the university.
     The physicist listens to his problem with careful thought and
says "I think I can come up with a solution.  Leave the chickens here
and come back in two weeks."   The excited farmer goes home to tend to
his other farm duties.

      Two weeks roll by and the farmer drives back to the university.
He walks into the physicists office and the physicists is ecstatic
with the information he has.  He says "I've solved your problem!
It's really rather simple.  Sit down there and I'll explain it to
you."  So the physicist starts drawing on the blackboard...
He draws a circle with a beak on it... "First, we assume a spherical
chicken."