Release that snake.  It is currently too small to be a threat even to hatchlings.  Adult snakes more problematic but losses when they occur are usually light.  I have lost very few chickens to snakes but have lost lots songbirds, rabbits and fish to them.  Chicks should be easy to protect by keeping vulnerable birds up and in a box snake can not crawl into.  You could also rent my dogs as they kill and eat snakes of all flavors.
	
		
			
		
		
	
				
			
	
 I feel a little bad killing them because they eat mice and bad bugs, so I let them out in the canyons here. In my neighborhood, they are usually trying to find water to drink. But we have rattlesnakes here too, so you have to be careful what you pick up. But I would agree with the other posters; from your photo I would think it is a rat snake or a very large garter snake. However, you are in FL, so you probably have a whole zoo of different snakes to choose from. 
		
		
	
	
	