The ducks and geese just don't know what to do with ice. They want a bath and try to dive into their frozen pond, but for whatever reason these days, the water is as hard as ice. We dump out the ice and pour in water, and they enjoy it a lot. But if they take a break from splashing, it freezes up again.
Bathing and splashing keeps our birds healthy: it allows them to clean their bodies and their mouths and noses, and large quantities of water ensure that they stay healthy with adequate water in their diet. Healthy birds are more productive birds, they are happier birds and produce with higher quality.
We wash our other animals periodically too: our cows, horses and camelids get a bath every month. Our goats get a brush down or a bath then too, but the goats are our cleanest animals. They are also our most hardy. Cleanliness makes animals stronger. That's why we also clean out pens every week. While some farms simply pile up manure in a corner, we take it out for composting, either in the ground in the gardens, or in compost bins for aging. This is better for the gardens and better for the animals (and the reason why we put our gardens so close to the animal pens - we don't have to carry manure so far!).
In the wild, ducks and chickens would be eating not only vegetable matter and seeds, but plenty of bugs. We have very few bugs in the summer because we have so little manure hanging about. What few bugs there are usually get eaten by the ducks and chickens who, though they are free to roam, like to hang out in the pens where they stand the best chance at getting the odd fly or mosquito. Sometimes a duck will chase a fly dozens of feet (and usually will catch it). In the wild, most animals don't have a need to bathe, but ducks and geese and other water birds do. And cattle and horses do when they are kept in a pen. It's important to keep in mind the needs of animals to make sure they are healthy, happy and productive.