Treat bags are bought from a picture and judged four months later on a shelf. These four decisions are what decide the second part.
The barrier has to work from the inside
Most food packaging is specified to keep oxygen and moisture out. Dog treats are fatty, and fat migrates outward through the bag. A grease-resistant inner layer is what stops it.
If your current bags develop a dark translucent patch that spreads up the front, that is what you are looking at, and it is a film problem rather than a storage one.
The closure is not a detail here
A treat bag is opened several times a day, frequently one-handed. That is a much harder life than a coffee bag or a snack pouch gets.
Specify a zipper rated for repeated use and ask how many cycles. A press-to-close strip that stops sealing on the fourth opening has cancelled out the barrier you paid for, because from then on the bag lives open.
Windows sell treats and show every fault
A window sells jerky and dried fish better than any photograph on the front of a bag. It is also the thinnest part of the pack.
Choose the window film for an oily product or it will haze, and place the window above the bottom gusset. A window that runs into the base fills with crumbs and grease and makes fresh product look like the end of the bag.
Format follows who is carrying it
Retail bags stand on a shelf. Sachets live in a pocket and win you new customers at vets, shows and training classes. Bulk sacks get carried full, which means a heavier gauge, a handle reinforced into the structure and a closure rated for the weight.
A scaled-up retail bag is not a bulk sack, and it will tear its handle out the first time somebody lifts it.
What to send when you ask for a quote
Artwork, fill weight, how oily the treats are, how long the bag needs to sit on a shelf, and whether you want a window. That is enough for a real quote and a mockup the same day.
Leave room for your labelling panel. What goes in it is between you and whoever advises you on pet-food regulations; we will hold the space.