The Animals

In the novel "Do Androids Dream of Electric Sheep" all animals are on the brink of extinction. There is a lot of emphasis on this. From what I can remember I think Deckard had an artificial sheep on the roof-top of his appartment (please correct me if I am wrong). In Blade Runner we know of the artificial snake and owl. We also see what appears to be a black-market trade with animal handlers on the streets. During Deckard's Voight-Kampff test on Rachael we notice that a lot of the questions are based on animals and animal-products. My question is this: Did Ridley Scott want his audience to think about the current situation with the extinction of animals or was he paying homage to Phillip K Dick's novel?