This is a bit late, sorry.
Here's 3 pieces of evidence that I think say he will be alive: (spoilers obviously)
1. He wasn't featured on The Talking Dead. Nearly every single main character that died has been interviewed right after the episode ends, but not Glenn.
2. This 'death' is way too uneventful. Look at some of the past main characters' deaths: Andrea, Hershel, the Governor (edit, also Shane and Bob)... all very dramatic deaths that had a large buildup. This supposed death? Basically no buildup & very sudden.
3. (warning, slightly gruesome details) If you watch the segment closely again, you'll realize that there are what appear to be intestines coming out from a body. Walkers are seen chewing way higher up than Glenn's lower torso region, suggesting that it is actually Nick's (whose body is laying on top of Glenn) intestines that are being eaten.
Add all this to the fact that there is a space underneath the dumpster for Glenn to hide after getting Nick's body off of him where walkers are likely not going to be able to eat him, while another character either kills the walkers or distracts them.
I may just be in denial as Glenn was one of my favourite characters, but I am quite convinced he's alive.
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