can you substitute the pork?

You can, but unless you're Jewish or Muslim I wouldn't. There is nothing else that tastes and has the texture of pork. Smoked turkey comes the closest to the flavor, but it's not the same.

Pork is traditional but yes, you can use chicken, turkey or even minced fish. SoManyMiles.com

I made this tonight and it was so good. I did use pork, but beef, bison or lamb would be good.

You probably use ground chicken or turkey instead of the pork.