Why did they give birth to spotted, blotched and Akudim animals?
Malbim: This was a miracle, so no matter what Lavan would say (is Yaakov's wage), Yaakov will receive some of them.
Ha'amek Davar: It was primarily Hashgachah, but Yaakov did some action, so it would be a hidden miracle. A small act below causes a great act above. This is a Siman l'Banim - Jews in exile will act with Chochmah, and Hashem will give to them success.
Why doesn't the verse record that any rouge-colored sheep were born?
Gur Aryeh (to 30:40): Any rouge-colored sheep were born naturally, and there is no need to mention them.