Why did Yaakov propose his payment scheme?
In Vayetze, Genesis 30:25–43, Jacob and Laban come to and execute a strange agreement:
Jacob agrees to tend Laban's sheep under a payment scheme as follows: First (as explained by Rashi to verse 32), Laban separates all the speckled and spotted goats and all the brown sheep, and gives them to his sons to tend separately. Jacob tends the remaining animals. Then, any speckled or spotted goats or brown sheep that are born thereafter from among the animals that Jacob tends constitute his wages.
And so it was. Jacob used strategic husbandry to get the animals to be born colored. Laban (as explained by Rashi to 31:7 and 31:41) kept changing Jacob's wages, from animals with one kind of marking to animals with another, but the animals kept being born to benefit Jacob (31:8).
My question is — why did Jacob propose such a deal? I would think (on no particular basis) that shepherds would normally be paid either in cash or perhaps in a percentage of sheep born that year. Why did he propose such a strange payment scheme? Is it perhaps because he knew he could get the animals to be born that way? If so, is that due to whatever husbandry tricks he knew or because of faith that God with intervene to his benefit?