How can she go about getting custody of her unborn child? What are her chances of this happening?

Probably high (the chances not the individual). She should see if she can get a lawyer (pro bono) from one of these services ... http://www.michiganlegalaid.org/findOrgAll

I don't think her chances are so high -- father's have rights too.

Why does she want to deny her child access to it's father? Fathers are important!

I agree - unless there is some reason he would be unfit or harmful for the child. You want your cake and eat it too in a sense - you want him to pay for the child, but not be in his life - not fair is it?

I would think a mother would want what is best for her baby. In most cases, it would be best for a child to know and have his/her dad as part of the child's life. Why wouldn't she want this for her child?

Totally agree that the father, unless impaired in some way, should be in the child's life on a regular basis. It sounds to me as if the same kind of immaturity that led the young lady to have sex without adequate protection is now leading her to think in such a restrictive manner. Not good for the kiddo at all. Uncomfortable for her? Too bad.
Joe(only 18 years of discomfort to go)Nation

What evidence does she have that the father would be a bad father?

Dads are important.

He has anger problems. He punches holes in his walls and he also punched his truck and put a huge dent in his truck

She will have full time custodial rights.

He might have to petition the court for visitation rights. They can be supervised.

In that case, I guess she's made more than one bad decision.

Perhaps the child could be given up for adoption - to parents who are better at decision-making.

Daddy-to-be needs anger management and both parties need parenting classes. Many young men punch holes in things, it's when that is transfered to violence against people that the big trouble starts. If the father wants visits he will probably be awarded them, and if a problem arises they will become supervised visits. No judge will award child support without considering the father's interactive role. I agree with ehBeth that adoption would be the best option, but I doubt it will happen. Poor kid, what a sad start to life.