Any vet techs or dog people know what this is on my dog?

Her fur is standing up and falls out in little chunks. She’s not scratching or itching. Her fur is super thick so it’s hard for me to see but I don’t see any redness or inflammation, but the white undercoat is quite literally just falling out if you run your hand through it. Her fur is not usually like this, it usually lays flat and silky.

She is mixed breed Australian cattle dog and greyhound.