When exporting LODs for use in Unity, textures that have alpha channels (such as hair) lose their alpha channel.

To reproduce:
* Create a character with hair
* Export to Unity and generate LODs
* Import to Unity
* Notice the LODs have no alpha channel on the hair which means they cannot be used for close-up rendering

To fix this:

1. The baked texture should include the alpha channels of the source textures
and
2. There should be an option for hair to be on a separate material (just like eyebrows)