Why shave sheep in winter?

Why shear a sheep in winter when it's cold? And can animals count? For instance, does a mother duck know how many ducklings she's got? Also, how does coronavirus infection alter our sense of smell and taste? Why do geese and turkeys chase people? How do artificial sweeteners work, and can they be harmful? When it comes to survival of the fittest, what constitutes "the fittest"? What brings asteroids onto a collision course with the Earth? Dr Chris joins Kieno Kammies to answer this week's crop of farmyard-inspired - and other - questions...