My guess would be that it has something to do with the sprouts being "heirloom." 2000 is a lot of sprouts! May I ask what you plan on doing with all those plants? Have you been in touch with the company you ordered them from?
I figured it out. I'm very new to all this, having grown up and spent most of my life in Chicago and now living out in the country, and used dirt from outside which apparently had other seeds in it. My girlfriend and I are going to plant all 2000 seeds.. we're on 200 acres of land and decided to begin making use of it by growing things. So far we've constructed a simple indoor grow room and have been learning a lot through trial and error.. mostly error