In my loft Peter my pigeons keel feathers change all the time....What I have noticed is when one of mine is really in form and normally before a good win or top fed position etc(not that I have had many)...their keel feathers are parted showing the keel slightly....maybe because the way they have blew up by the end of the week who knows...But what I will say is all my best pigeons have good healthly feathers...