A tedder machine is like a really big comb for the grass that animals eat. Imagine someone is brushing your hair with a big comb that has lots of teeth. That's kind of what a tedder machine does to the grass. It helps to spread the grass out and fluff it up so that it can dry more easily.
After farmers cut the grass, they need to dry it out before they can use it as food for their animals. The tedder machine helps to speed up this process by turning the grass over and over again, which helps it dry faster.
The tedder machine has big wheels that turn around and around, and these wheels have lots of little arms on them that stick out. As the machine moves across the field, these arms grab the grass and fling it up into the air. This helps to get more air and sunlight to the grass, which helps it dry faster.
After the tedder machine is done, the grass looks all fluffy and spread out like a big comfy bed. This makes it easier for the farmers to come back later and gather up all the grass to feed their animals.