Prewashing skeins of cotton?

I am looking to knit a stuffed toy for a baby out of 100% organic cotton yarn, with intent for it to be machine washable. However, I am wondering if prewashing the skeins before knitting with them is viable for getting any shrinkage out of the way, like with fabric for sewing? Or would this potentially ruin the yarn? (Of course they would need to be secured to avoid unraveling and tangling first.) Any advice is appreciated.

No, the best way to tell if it’ll shrink is to knit a largish swatch and wash that. Skeins of yarn aren’t washable like pieces of fabric.