Ate slightly undercooked chicken?

Probably pretty low since you ate so little. I'm sure you'll be fine, but see a doctor if you start to feel sick within the next few days. Good luck!

It can't be “about half undercooked” - it's either undercooked or it's not.

It REALLY isn't a sensible thing to do to eat undercooked chicken (and there's NO mistaking it).

If it was contaminated with salmonella then you have a pretty good chance of contracting it. If it wasn't then you won't.

No one here can say how likely it is that it was infected with salmonella especially since you din't even tell us what country it was bought in.

@Kalia - I don't understand the first part of your comment, sorry. Chicken bought in the USA could be contaminated with salmonella (it's less likely than in some other places though).

To correct a couple of other answers: the amount you ate makes no difference. It's not like consuming something poisonous- the bacteria reproduces inside your body.

Normally it takes 12 - 72 hours for symptoms to appear.

You should be OK. If it was infected and the cooking wasn't enough to kill any bacteria, you'd be feeling sick by now. Salmonella, listeria and E-coli are pretty quick in doing what they do.

Very very slim .......