Chocolate Labrador skin problem

Hi everyone, I'm new to this so bear with me.
I have a male chocolate Lab about 6 years old. He is a big fella but not fat as we live close to mountains in mid wales, where we spend most of our time.
For the last few months I have noticed he has a non irritable bald patch on his right hand side and his coat has dulled.
We feed him on a dry mix that we soak in warm water first to soften.
We even give him fish oil tablets to give him some oil for his coat.
I am considering switching his food to a raw meat diet and also given him a raw egg a couple of times a week, Am i moving in the right direction doing this.

What does the vet say about the bald patch? Have you had him tested for thyroid issues? It can cause hair loss. You need to rule out medical conditions before you start thinking along dietary lines

The vet tested for diabetes, but did not take a skin sample which we thought she would have. But did take blood.
It came back and we were given the okay. But I don't think thyroid was even mentioned.