A Zed & Two Noughts (1985) on Netflix

A Zed and Two Noughts follows the lives of Alba Bewick, and Oswald and Oliver Deuce. When an accident with a white swan leaves Alba without a leg and the Deuce's wives dead the trio must cope with a scheming doctor and their own grief. It is the brothers' grief that leads to their fixation with natural decay of animal flesh. As they progress in their grief process they seek more and more complex animals to watch fade away. The brothers' obsessions leaves them in peril of losing their jobs and drives them closer to the person at the wheel when their wives perished, Alba. In the end, their insatiable apetite for decay leads them to the top of the food chain - Humans. But who must meet an end for the evolution of Oliver and Oswald's grief?