You can obtain animal treats by purchasing them from Agnes and Agatha’s garden stall in the Finchwick district of Henford-on-Bagley or winning them by participating in the Finchwick Fair, held every Saturday. You may also receive animal treats as gifts from wild animals like bunnies and birds.
Once you’ve obtained an animal treat and fed it to an animal for the first time, you’ll unlock the recipe to make that treat yourself in your notebook. You can check the notebook at any time to see what animal treat recipes you’ve unlocked and what is needed for each recipe. You can make the animal treats by clicking on the fridge and selecting Create Animal Treats.
https://simscommunity.info/2021/07/22/the-sims-4-cottage-living-all-about-animal-treats/