Yes, you can use cheese, canned food, etc., but I was experimenting and it turned out well. I don't have any specific measurements so I'll just go based on general directions. I didn't pay any attention to chemistry so I know some things I added probably canceled each other out.

Dogs and probably cats are attracted to smelly foods. The smellier the better. So I decided to use some tuna fish.

I ground it up really fine in a food processor, keeping the liquid. I put about 1/2 a cup in a bowl. I added about a tablespoon of fish sauce. (Used in Thai, Japanese, Asian cooking). Then about a teaspoon of vinegar, 1/2 tsp of lemon juice and a dash of salt for preservation. I put in about 1/2 to 1 tsp of oil. Canola maybe.

I added about 1/4 tsp of yeast to about a tsp of warm water with a dash of sugar and let it sit. When it began to foam I added it.

I mixed it all together and then added a little bit of baking powder and mixed it again. Then some corn starch, about 2 tbls.

I kept adding whole wheat flour until it was malleable but starting to crumble because of dryness.

I put as much water as I thought would make it moist (without being sticky) but still dry enough to hold it's shape without drooping too much when I picked it up.

I added about 1/2 a packet of Knox unflavored gelatin and boiled it. Then I added it to the dough and mixed it. If you end up adding too much liquid to your batter, just add more tuna, flour and corn starch.

Making sure it wasn't too hot, I cut little strips and wound them around my finger, forming a cup. Keep a paper towel lightly oiled to re-oil your fingers between each strip.

I put each one in the freezer as soon as I formed it and made sure there were no seams.

I then boiled the other half of the gelatin with about 1/2 a cup of water and placed it in a cup.

After they were in there about 10 minutes I used a spoon with holes in it to individually dunk each one. I let them sit in there about 30 seconds each.

Then they went into the fridge. After they firmed up and the outside dried a little, I put them in a sandwich bag and they went back into the fridge to use.

I took out two and have them in a sandwich bag in a cabinet to see how long they can survive outside the fridge without going bad.

Since they have four preservatives: sugar, salt, vinegar and lemon juice, I wanted to see how effective it'd be. If you have fresh rosemary, it might contribute a little bit of it's preservative powers.

I make dog treats for Ginger very often and they last a long time in a cool, dry place when I use those preservatives. But those dry out, they don't stay soft like the pill pockets would have to.

Anyways, it sounds like a lot of work when I could just shell out the money to buy the pockets or just wrap pills in cheese but whatever. I was bored!