Does the cocoon have a lot of silk around it, where you could stick something through the silk, like a pipe stem cleaner, and attach it to a tree or bush without piercing the pupae inside?

Do you have a zip up laundry hamper or other such vented "cage" you could put it in outside somewhere up high enough to not be in the line of ants? You would be sure to see what emerges that way. You could make a bag out of netting to put it in and then hang this bag in a tree.

Can you make a picture of this cocoon and post it so we could see what type it is? There are many types of cocoons and many ways you could keep it safe.

Sherry

Cocoons are not always attached to something. For example, luna cocoons are supposed to be amongst the leaf litter.

If you want to protect it, put it in a container. Provide something that allows the moth to be able to climb up to a place where its wings can fully open. Check the container everyday, preferably shortly before lights out. This is because most moths fly in the dark. If you leave a moth in the dark in a container, it will beat itself up trying to get out.

When will it hatch? Either "sometime this year" or "the cocoon might already be empty."

KC