I'm just going to throw this in also.
Information from
Exhibition Poultry Keeping by David Scrivener 2005
White plumage can be caused by three genes:
S, c and I. S is the sex-linked gene silver, as seen on Light Sussex.
The opposite gene to it is gold (s). This gene only changes the "red" or "gold" parts of an E locus plumage pattern, not black parts of those patterns.
Those reader old enough to remember the famous Rhode Island Red x Light Sussex sex-linked crosses that were once the mainstay of
poultry farms before the age of hybrids will know that the silver gene is basically,
but not completely dominate to gold, and that there are often genes affecting the shade of "golds".
The crossbred cockerels are essentilly the same color as there light Sussex mothers,
but have some gold on there shoulders, and the crossbred pullets are gold, but a few shades lighter than their Rhode Island Red father.
So in reading that I know that the op's bird are not out of a R.I.Red rooster over a Light Sussex hen.
Now if you cross a Light sussex rooster over a R.I. Red hen. The roosters would be a cream color with Black tails and the hens should be the Columbian pattern with some red in the shoulders.
So I would say that the Light Sussex was not a parent to the op's birds.....
Chris
