Hi Birdman, could you inform us your pond's size? and zone? It sounds like you are a beginner and Ray's answer is just about to cover everything.
One day when the koi bug gets you, please write back ... and we have a new set of selection for you.
PapaBear, after all those years have you not learned how to keep the girls from trouble?
For female koi, the secret is in the winter fasting technique. Most people re-feed early, like March or so, and these food energy would go to eggs production. Feeding early is also stress the entire pond if the good bacteria are yet to re-established. Delaying the feeing until May has produced good result for me. An all female pond is also help but nothing is perfect. Once you severely fast them in the winter don't even think about further fasting for summer koi shows. MA Le