The spawn is something that few here on forum understand, less than maybe one percent of the crappie spawn at a time. And like any egg you want to hatch you have to have the right temp for what ever time period. Since the crappie is doing it in the wild they wait until the water temp. is on the high side for them. This is sort of how it works, the male and female comes in to the shallow water at the same time and do their thing. here is the way it works : when the water is right the male will pick out a female and he goes in to built a nest. when ready he goes back out and get the female and she lays the eggs in the nest. The male stays on the eggs till they hatch and he looks out for the little ones for about 5 days. At that time they make a run for the grass line are what ever the male has picked out for them. May sound easy but they are both in very bad shape after the spawn. The female will feed heavy for about a week to be ready. This is the best time of year to get a three pound fish, as a 2.4-2.5 female full of eggs and shad can go 3. Any time you are fishing shallow and getting males if they show they have been building a nest or fighting move on because if you catch the male a bigger fish will eat the small ones. The spawn is best after they have been after it a while and you have females that is post, pre, and spawning at the same time in the same water. On Texas lakes in the north it ends about May 1 or so, and takes from 6-8 weeks to cover the lake most years. Just how fast the water gets right.