i'm not really sure. I've never seen those eyes before but they do look great. on a side note, i'll see you at rainfurrest!

I would assume these people just don't really like breathing haha. The eyes I assume don't fog up because the eyes on the inside don't have the holes in them so no breath to go in the clear parts. You could ways add in a small fan since the mouth might not open too much, but trust me even the little bit helps a lot with the fan.
Also OMG BURD!!! So cute! The noes might be able to help with that because bird have the big nose holes in convenient places.
The plastic pieces I think you could either try the new clear worlba and put it over some other sphere thing and shape them that way, or buy these half clear balls at hobby lobby.

RainX sells a de-fogging buff-on liquid~

i havnt used any in my crux suit as the mouth takes out all my breath, though my right eye still fogs up alittle so when i get the time it could bar some experimentation.

also there could be mesh vents in the ears~ that is something i want to experiment more with personally~ mesh vents higher up in the head work great for siphoning heat out~ a large number of mascot heads utilize this technique

i Love talking shop and technique but i just got back from a two and a half hour drive, so uh~ if anything seems weirdly worded or unclear just lemme know.

Wouldn't the plastic alter vision somewhat as well?
If I do a bird fursuit, there won't be any ears to hide vents up top.

not too much, i kept my lenses at a shallow angle so there is little to no (word starts with a D but it just slipped my mind)

is the bird a completely smooth head? does it have hair feathers? ear holes on the sides?

but even so my untreated lenses dont fog up too badly since the mouths of my suit line up with the nose and mouth of the performer (most of the time)

Omigosh that bird sketch is SO CUTE!! :D I can't wait to see it in suit form, I think I might die from cuteness!!

It's based on a Fischer's Turaco and it's something I've been sort of thinking about since I started making fursuits. I just love me some burds!

That's amazing! That's one fierce mohawk, lol.