What specific physical vulnerability do single-combed Leghorns face in harsh winters?

Frostbite on their large combs and wattles

Although Leghorns originate from the warm, Mediterranean region of Italy and possess adaptations like large combs and wattles that aid in shedding excess body heat during warmer months, these very structures become a liability in cold climates. The large, floppy single combs common to many Leghorn types are highly susceptible to freezing when temperatures drop significantly. This susceptibility leads to frostbite, which can damage the tissue of the comb and wattles. To mitigate this vulnerability in harsh winters, keepers must take preventative action, such as applying protective salves like beeswax-based products to repel moisture, or, ideally, selecting the Rose Comb variety, which has a smaller, less exposed comb structure less prone to freezing.