The animals have disappeared.

[Himawari]

Hi, On the 12th day of spring of my second year, I found my first frog on the farm. But all the other animals are gone. I set up a house for four small animal species and the animals lived there until the day before. There were also many animals that did not live in houses.
Is this such an event? Or did I do something wrong?　Restarting the game does not change it.

[AirysPaw]

have you been feeding them? They leave if you don't

[1K.ey]

Put out a food bowl and fill it with food. You can find out your favorite dish by looking at the animal with a magnifying glass.

[Himawari]

Ahhh, I didn't know that! I had no idea how to feed them and had been putting food in the shed inventory, but I thought it was strange because the food was not decreasing.
Thank you both so much!!