FF is a curly-feathered bird, but to an extreme. The feathers are EXTREMELY fragile, and break easily. So it's best NOT to aim for an FF chicken at all. That's why most breeders just breed frizzle to smooth (like you see above) and get 50% frizzle, 50% smooth-feathered.
ff does not mean the chicken is a FRIZZLE CARRIER. There is no such thing as a smooth-feathered frizzle carrier. IF the chicken has frizzle gene, it will show up SOMEHOW. So ff just means the frizzle gene was NOT inherited. As we all know, chromosomes come in pairs. Ff means ONE chromosome inherited the gene, but the other one did NOT. However, since Frizzle always shows up, the one that DID inherit it will make the bird's feathers curl.
Can you get an FF that lives? Sure. But you better be ready to do a LOT of cleaning up from feathers falling out, and keep that bird indoors, because it will be extremely vulnerable to cold AND hot. Sunburn and frostbite are never pretty!
The rooster does NOT have to be the one with the frizzle gene, and the hen with the smooth. You can have a frizzle hen and a smooth rooster.
ANY bird that is purebred, is still purebred even with the frizzle gene. So if you have a frizzle bantam purebred cochin (most popular breed for frizzles), and you breed it to a smooth feathered purebred bantam cochin, the babies will all STILL be purebred bantam cochin. So even if they don't get the frizzle gene, they are still legally, accepted, APA standardized purebred bantam cochins. That's why it's most important to get a frizzle of a particular breed, and mate it to THAT breed. A frizzle purebred bantam cochin bred with a purebred bantam polish smooth feathered will get you mixed-breed chicks. But half of them will have curly feathers.
If anyone has questions about how this gene works, FEEL FREE to PM me. I have no problem answering questions about it.