Rashi, on Gen 30:40

“And Jacob separated the flock, and put the rods in the troughs before the eyes of the rams: and all the white and the black were Laban’s: and the rest were Jacob’s, when the flocks were separated one from the other.”

“והכשבים הפריד יעקב AND JACOB PARTED THE LAMBS — Those sheep that were thus born spotted on the ankles and speckled he separated and set apart by themselves, thus forming them into a separate flock. He led that spotted flock in front of ordinary sheep so that the faces of the sheep that followed behind them were gazing at them. This is what Scripture means in saying, “He set the faces of the flocks towards the spotted” — that the faces of the sheep were directed towards the spotted animals and towards all that were brownish which he found amongst Laban’s sheep (i. e., amongst the sickly sheep which Laban had left him; cf. Genesis 5:36). וישת לו עדרים means he formed them into a separate flock as I have already explained.”

Imported from an open dataset — not yet checked against the printed edition.