I had 5 hens during 2004 when we got hit 3 times. They could have taken shelter in the big enclosed laying box, but NO, they stayed out in the uncovered part of the coop throughout! Poor things. It's a wonder they didn't get sick, but they didn't.
I won't let that happen again. I have a lot more chickens now and a much larger covered area, but I'm sure the roof won't stay on in a hurricane plus the sides are entirely open. I will probably move them into one or more enclosed structures - my tack room, our small barn, my husband's shop, even our den. I have portable pens that I can set up, put plastic sheeting underneath, and a mesh cover on to keep them in.
We won't have to evacuate, though, because we are too far from the coast for that. My mom, in New Orleans, was thinking about getting a few laying hens, but the thought of evacuating with chickens in tow deterred her. They evacuate about once a year.
A very fine gentleman I knew that lived near the Mississippi Gulf Coast during Katrina had raised a nice flock of quail and game birds that he loved. He evacuated before the storm hit, and the entire neighborhood went under several feet of water - an area that had never flooded before. All of his birds were drowned. It was more devastating to him than the loss of his home of many years.