So when it's first starting to develop, there is a circular vein around the embryo with veins going from it to to the chick. A lot of people mistake this for a blood ring. I don't think it looks underdeveloped. If it has veins and a fluttery heart, it's probably fine. Give it a few days and there should be some growth of embryo and the wall of veins.
	
		
			
		
		
	
				
			 
	 
 
		 
			
		
		
		
	
	
			
		 
 
		 
 
		 
			
		
		
		
	
	
			
		
 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		 
 
		