You are not crossing a Buff Orp Rooster with a Delaware.  You are crossing a mixed Silkie/Buff Orp rooster with a Delaware.  What genetics is the Silkie part of that rooster contributing?  
If the mixed rooster is red, there is a chance you will get red sex link chicks from that cross. There are no guarantees but it might work.
	
		
			
		
		
	
				
			If the mixed rooster is red, there is a chance you will get red sex link chicks from that cross. There are no guarantees but it might work.
	