Each breeder must weigh what he is actually wanting to accomplish and how quickly he/she wants to accomplish it.  This could be more detailed, but it is meant to be a quick reference of guidelines to help the breeder choice what direction he/she wants to go and what kind of risk he wants to take.  In-breeding will require the most and frequent culling of these three.  There is another spreading system called Hybridization that we have stayed away from because it is the crossing of  two separate breads and it is something that should be avoided if you are not attempting to develop another breed These three systems are used by those who are just attempting to improve an existing breed in their loft..