Is it safe for ponies to eat raw potato skin?

No, ponies should not eat raw potato skin. While a small amount of cooked plain potato is not toxic to ponies and can even be part of a balanced diet, raw potato skin contains a compound called solanine that is toxic to horses and ponies. Solanine can cause a variety of health problems in horses, including digestive upset, nervous system problems, and respiratory issues. In severe cases, solanine poisoning can even be fatal.

Therefore, it's best to avoid giving your pony raw potatoes or potato skins, and to always err on the side of caution when introducing new foods to their diet.