I have 3 children. Ages 7, 9 and 11. I am divorced and have been for 4 years. My ex husband(father of all 3), has not seen or even spoken to my children in 3 years. He has not paid a dime in child support in over two years. He is in and out of jail for various things. Do I stand a chance of having his parental rights terminated? If so how do I go about filing?

Simple... you don't. I suggest doing a search on the topic and do a lot of reading.

Taking away parental rights isn't the same as taking the playstation away from your kid.

A court can do it... YOU however can't. And the court rarely ever does.

You might want to check out this sticky:
https://www.askmehelpdesk.com/family-law/signing-over-rights-read-first-116098.html

No I don't think you stand a chance. He is not exercising his rights so there seems no reason to terminate them.

Agree, he does not have to use his rights, in the US each state has various laws, you can file in court, and serve him notice, and if he does not show up, the judge MAY, but I doubt he will even then, And in most cases even if he agrees and will sign them over, unless there is a new partner to adopt, they seldom allow the one parent to even give up the rights, and almost never have them taken for merely non contact