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.