Many of us do keep oyster shell out even when feeding layer.  Each hen is different and do not read that the % of calcium in layer is all they need.  You could have some hens that just need more for a number of reasons.  If you have no shell or laying problems without oyster shell when feeding layer, then great.  I keep it out for cheap insurance.
	
		
			
		
		
	
				
			 
	 
 
		 
			
		
		
		
	
	
			
		 
 
		 
 
		
 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		