Millions? So there were slightly fewer than 4 million slaves in the Confederacy in 1861. Are you saying all the former slaves died of starvation and exposure? Half? Two thirds? What?
But this sounds like a good topic for you to research. How many former slaves died from starvation and exposure in the aftermath of the civil war?
I've seen numbers all over the place, and some of the articles didn't distinguish whether or not the population in question was black or white.