Pine nut cookies will keep in a tightly sealed container at room temperature for up to 10 days. They will gradually lose their freshness, but they keep much longer than most cookies. They can also be frozen in a zip top bag for up to 3 months. If you plan on feeding, undercook them slightly, then thaw in the refrigerator and re-crisp in the oven at 300 degrees F for about 5 minutes.