Only a quarter of the offpsring from that backcross will be red pyle. 1/4 will be black, 1/4 white, 1/4 bbred. You will need to hatch multiple to get what you want.
That is all supposing that those are dominant white. There is always a chance they are recessive white, which will never give you red pyle.
If they offpsring are white when crossed: dominant white. If not, recessive white.