
We live very close to the south downs and our dogs love to eat various grasses and herbs which they can spend quiet some time looking for the right ones.
At the moment my old lady (almost 13 ) is eating Goose grass / Cleavers every day. She is never sick and I am sure she knows what she is doing, I would not stop her either.
The other dogs hunt around the field finding the "right poo" to eat from our donkeys, they love the softer almost sloppy ones.
Later in the summer they will line up along a bramble bush all looking for blackberries which they pick for themselves.
These types of foraging are natural and healthy.