It's a simple problem. We have one geriatric cat who barely eats and two Norfolk Terriers who love cat food. Turn your back for a minute and the dogs will seek out the cat food and scarf it. The dogs put on a show of being sorry if we catch them, but as soon as they have another chance, they go for it again. We tried lifting the food while the dogs were out, but whenever we forgot, they got into it again. We put up a store-bought gate, reasoning that the cat could jump over and the dogs couldn't, and it worked sometimes. Our dog Bert got pretty good at jumping it and started peeing all over the cat food dishes once he'd cleaned them out. We clearly needed to talk to that dog.
We also worried about the cat. She's not as young as she once was, and she seemed to be struggling a little with the gate. She needed easier access to her food and to her litter box (which is in the same fenced-off area).
But what would allow easy access for a rickety cat while excluding two fully functional terriers?
The answer involves corrugated cardboard and a whole lot of packing tape. You will also need a dead-end hallway or seldom-used closet, bathroom, or other space that you can wall off to keep the cat food/box in.
Step 1: Sizing the Hole
Begin by measuring the width of your cat's shoulders. It'll look at you funny, but they always do that. Do the same to the dog. If the dog is wider than the cat, you're in business.
Cut a hole in a cardboard box. Make it the width of the cat's shoulders, and double that for the height. Get a cat treat. Put the cat in the box, close the box, and lure the cat out through the hole. If the hole is too small, enlarge it a bit. When the cat can easily pass in and out, put the offending dog in the box and attempt to lure him/her out with a treat. Bert eventually managed to bend the cardboard enough to squeeze out, but he didn't seem to enjoy the process, or want to repeat it. I decided this was good enough, and settled on a 3" x 6" hole. (Your measurements will vary, of course.)
Step 2: Building the Wall
I decided to build around the existing gate. It's stable, it's fairly sturdy, and the only thing it really needed was a taller top and a passage. I shortened it to open up a passage and then filled in the resulting gap with cardboard. The top was too low, but the two-piece design made it easy to sandwich a piece of cardboard in between to act as a parapet. Work with what you have here, and be sure to tie it securely to the walls. Think like a dog. If the wall's sturdy, but it's not tied to the wall, it's going to get pushed out of the way.
I cut the 3"x6" hole in the cardboard near the floor and reinforced it with more cardboard. The additional cardboard adds stiffness, preventing the dog from deforming the hole and muscling its way through. If you discover the hole is too large, or in the wrong place, just cut an appropriately sized/placed hole in another piece of cardboard, tape it on over the first sheet, and trim the first sheet as necessary. I raised the hole a few inches above floor level so that the cat wouldn't have to crouch.
I found a smaller box and fit it over the backside of the hole, essentially making a little hallway going straight back. I cut an exit hole in the side of the box, not the end. This little hallway bit means that you can't see the cat food from the entry hole. My hope is that the dogs will stare at the cat food through the gate and ignore the hole entirely. They're also a lot less flexible than the cat, so if they do force their way past the first hole, they'll have a difficult time making that last turn.
Step 3: Testing
I went and grabbed a plate of salmon, put it behind the wall, and set the cat in front of it. She didn't get it right away, so I set her in front of the hole and gave her a push. She climbed through, found the fish, and figured the arrangement out pretty quickly from there. She goes in and out many times a day going to her litter box and her food, and the dogs, so far at least, don't.
Turns out PB videos won't embed, but oh well, here they are anyway, just in case you needed to see Ilsa the cat walk through the completed wall.
There you have it, a cheap and easy way to keep small dogs out of the cat food. It could be made to look better, to come apart for storage, to match the decor, whatever you want, with a little extra effort and materials. Paint it up like a castle wall and it doubles as a project to do with your kids.
Come to think of it, this could keep your toddler out of the cat food as well.