The frizzling gene is a single gene dominant.
f+f+ is normal feathered
Ff+ is frizzled
FF is super frizzled
A super frizzled bird is partially bald and the growing feathers are so brittle that they repeatedly break off. For this reason the usual mating is Normal x Frizzle because this gives 50% of each with no Super Frizzles.
However this simple pattern of inheritance is complicated by the existance of another gene called the frizzle modifier gene. In this case the mutation is recessive so:-
Fm+Fm+ is normal
Fm+fm is normal but a carrier
fmfm is modified
The frizzle modified bird prevents the frizzled bird growing frizzled feathers so it looks completely, or nearly completely, normal. So in this case a bird can carry the frizzle gene but not be frizzled. But if this bird is then mated to a normal bird that does not have the frizzle modifier gene then half the offspring will come frizzled which gives the impression that the frizzle gene itself has been carried as a recessive even though this is not the case.
Not an easy one to get your head around and in the majority of cases where a frizzled bird crops up from two normals then its due to a mismating. But nevertheless in some cases this other explanation is correct.