Producing your own replacement gilts is a good option for larger herds. Choice recommends 10 to 12% of your herd be Grandparents (GP’s). With that size of a GP herd, your pool of replacement gilts will be large enough that you are only selecting the best of the best gilts to return to your herd. Some companies recommend the GP herd be at 8%, but then your replacement gilt pool is small and you have the potential of selecting gilts to return to your herd that are below normal standards. This will reduce sow longevity in your herd and a higher sow mortality and sow cull rate.