Genesis 30:39 - Matthew Poole's English Annotations on the Holy Bible

The flocks conceived; Heb. were heated, i.e. inflamed or excited, and disposed to conceive, and this in a more than ordinary manner by the Divine disposal. The event hath some foundation in nature, because of the great power of imagination; and there are divers instances in many authors, both of women and of beasts, who either by the strong fancying, or by the actual and frequent contemplation, of some certain objects, have brought forth young ones exactly of the same colour and complexion, as one did an Ethiopian, &c. But the providence of God was the principal cause of this effect, without which the productions of that kind would neither have been so many nor so certain. This policy of Jacob's could scarcely be excused from deceit and injustice, if it were not manifest that it was done by the direction and authority of the sovereign Lord of all estates, Genesis 31:9,11, &c., who may take them from one, and give them to another, as it pleaseth him; who also observed Laban's injustice, and gave to Jacob no more than he abundantly deserved from Laban.