Came across what Jerry Foley says about single combs, thought I'd post it in case you were still curious.
"Occasionally, you will hatch a
Wyandotte that possesses a single
comb rather than the desired rose
comb. This is a disqualifying fault.
The single comb is a recessive gene
that still hides within many
individuals of the breed. When you
bred two birds together that
carry a single copy of the single
comb gene, 25% of their offspring
will have a single comb. Some
breeders believe having the single
comb gene in their flock improves
fertility, but I am not here to
argue about that. Personally, I cull
all single combed birds from my
flock. It has not been my
experience that breeding only rose
comb to rose comb has anything to
do with fertility. The decision to
use single combed birds in your
breeding program is a personal
choice that you as a breeder will
need to make.
However, don't throw the baby out
with the bath water. If you have
an exceptional bird with amazing
type and color, but it has some
faults in its comb, I would
carefully weigh the severity of
those comb faults against all the
good attributes the bird has to
offer. You may need to use this
bird in your breeding program and
just cull for combs the next
generation. BLRWs with excellent
Wyandotte type are hard to come
by. Unless you already have a
correctly combed bird of equal
quality in your flock, it would be
best to use this bird regardless of
a few faults."
So that's what the man of many wyandottes says about it.