https://www.google.com/amp/s/www.pbs.org/newshour/amp/updates/tthis-chicken-vaccine-makes-virus-dangerous
After reading this article I wonder if vaccination is in the best interest of all birds
Applying the genes to a Punnett square it would appear that a frizzle crossed with a frizzle would result in 50% frizzle, 25% smooth, and 25% undesirable curlies.