How common is a chicken allergy?

My cocker spaniel just turned 3 and has been dealing with ear and paw irritation. She’s had two ear infections that required vet care, and while treating the last one they mentioned potentially exploring if she might have a chicken allergy. They said an elimination of poultry from her diet would be the first phase of that exploration.

The paw licking is something her groomer has helped me keep an eye on. We’ve tried a few things, and right now I’m doing paw baths with the PetMed BP wash I found recommended here. Maybe related?

I recently went ahead and switched her food to (also mentioned on this sub) the Purina Pro Sensitive Skin and Stomach. I can defiantly see an improvement in her stools.

I’m mostly just wondering how common this has been found to be with other cocker owners, and if there’s anything else I should be looking into or thinking of.