This has been a problem since Poser 5.  When growing hair on a figure, it ends up kind of splotchy in areas.  Little bald patches in some places, a few weirdly long strands in others.  I'm not sure what the problem is, but it seems to happen at the edges of groups.

You can see it in my attempt at a down-covered dinosaur in the attached image.  At the back of the head.

I know some people have found a way around this (for example, Tiny's furred animals).  Does anyone know what the trick is?

 

I would think it's slight changes in resolution in different areas of the figure. Some faces are larger, some are smaller. The larger faces would make the area look more sparse than the smaller faces that would make the hair look more dense. Dynamic hair grows from a face (polygon).

Laurie

But what causes those occasional really long strands?  Shouldn't they all be the same length?

This happens even if the hair is all set to the same length with variation 0.