A method of forming a flexible packaging film includes providing a first web including a polymer sealant layer, the first web having a first major surface and a second major surface opposite the first major surface. A second web including a polymer outer layer is provided, the second web having a third major surface and a fourth major surface opposite the third major surface. An adhesive layer is applied to the second major surface and the first web is laminated to the third major surface. Prior to laminating the first web to the second web, one or more slits are formed in the second web.