weird render artifacts in chicken models

Heres an example:

Its a model from Yo franke, ‘levels/start_menu.blend’. I wanted to upload the blend, but many models are linked to it, i think its called ‘library’ in Blender. So if I just upload this blend many textures and models wont be in it and it will raise a warning. If you know of a way to pack the files into 1 blend i will upload it.

The problem is with the eyes. I dont think its caused by the ‘diffuse map’ or normal map as i tried disabling them.
Also, whats a diffuse map? Is it the same as specular map? Thats ‘gloss’ map in Panda, right?

EDIT: I think the eyes show up correctly when disabling “Env” button in “Material” panel, i wouldnt mind to know what that really does, and the other question still not solved,

Env is environment mapping is great for making mirrors and really shiny stuff like eyes.

See here:

I am guessing some thing is messed up in the previewer.

I know about environment mapping. But I didnt know that can be automated by having the egg file do it. But doesn’t look like it really works anyway.
It really messes z-order of the whole model.