Sounds like it might be a needlessly complex model, maybe with redundant polys right on top of each other, possibly with some strange Normal stuff going on. We’d have to see the model to tell. You might want to look at one of the head tutorials out there (sorry don’t have a good link at this point – anyone know a good one?) If you build simpler heads but this was just unusual, ignore me 🙂
If you had a cleaner simpler mesh the chances it working would greatly increase.
Hair layers should be no problem – eyebrows, sideburns particularly – but how many Hair objects are you using for the main hair? By the look of it one should do (maybe a couple but it’s not a bizarre hairdo)
Some more thoughts, what are the bounce and friction settings of the hair objects? And do you have any Hair to Hair turned on in the Hair objects Forces tabs?