Pros:

-Very creative, first map (i've seen) in a slaughterhouse.
-Each room is diverse, making it a fun-to-explore map
-Nowhere is safe forever, it forces you to move around and do different tactics.
-The map is believable, you could actually see it working and have people using it.
-(this is small, but it's still a pro) you can actually follow the path the meat takes, you didn't just have random tracks throughout.

Cons:

-The mist room. It's only one room, it would be cool to see the mist spill out into the hallway, or even as the time goes on to have it slowly fill the entire map to give it an eerie and creepy feel.
-It's a little small, adding outdoors area (like seeing where the meat goes out into trucks, e.t.c.) would be nice, and make it appeal to the audiences who prefer outdoors.

Conclusion:

Easily one of the best custom survival maps I've tried. The only cons are things that would make the map better as a whole, no bot glitches or bad nav meshes, no leaks. The design is well-thought out, it's fun to explore, it's fun to play in. Maybe consider the Con's for a second map, or something. All in all, excellent map.