I thought it was funny that y'all were so focused on the chickens that you didn't notice that one of the photos is a crime scene, with legs sticking into the frame..... but then I went to grab the pic to post here, and realized that NOLA.com cropped the legs out since the initial publication. Knowing that might make more sense if you're perusing the comments. Yes, the murder rate is so bad that we're kinda blase' about it anymore. [/digress]
My friend lives over in the Ninth Ward by the old SPCA, and there's a HUGE flock over there. I've seen 40-60 bantam and smallish chickens running around, with several chicks. The shed across the street from her has been abandoned since Katrina and has a chicken-sized "door" cut in the wall, which is where most of those live. She was adopted by a beautiful rooster for a while (which she named Roux), but some kids stole him out of her yard.
There was a rumor about a group of Cock Fighting Enthusiasts using the flooded/abandoned SPCA to house their birds shortly after Katrina, and then they were raided. I don't know if the birds were removed, or if the owners released the roos hoping to not be caught with them.
There were chickens all over town before the storm. In the poorer neighborhoods, they were pretty common, but contained. Now we've got big feral flocks and not many in yards, though the Boutique Backyard Chicken Movement is gaining ground.
Chickens are also a common device for casing property. Kids (6-10 years old) will run around with a chicken or two, and toss them into yards. They then feel like they can come onto your property to retrieve their "lost" chicken, all the while gauging your attention, door and window protection, dogs, cameras, contents of yards and/or sheds, etc. Then they'll either use the info themselves (I've had a former residence broken into and tossed by someone/s approx. 4.5' tall... nobody much larger could have made it through the broken glass left in the opening), or pass it on to big brother or daddy.