Every once in a while I have what I think is a Brilliant Idea. It's creative, it makes use of resources well, it fits the criterion for the objective perfectly. I've found that the key to using these ideas well is to do some research. If you have an idea that seems awesome and does things in a cool, creative new way in an old field there is often a reason it hasn't been used. This was the case with our most recent one.
Given the vast number of rocks, large and small dotting our property my lady and I have been looking for good ways to make use of them. It's prompted some good creative thinking, and for the most part the ideas have been good. Things like making stairs leading up a degrading slope, building retaining walls, making raised garden beds using rocks rather than wood.
When digging down to place the underground portion of the fence to keep predators away from the chickens use rocks instead of wire to keep the predators out.
We did some thought into it and found some refinements ourselves. Rather than using rock fill of small fist sized rocks, and big round rocks which animals could find holes through we could use the flat rocks all over the place. Indeed we could use the big slab like rocks. The plan was to make a 30" deep wall of these flat rocks under ground to make sure we were below the frost line and avoid buckling. At the base of that flat wall, we were going to be placing an approximately 2 foot apron of yet more slab rocks. The purpose of that flat base was to keep animals from just being stubborn enough to dig under the whole 30" deep rock wall. It seemed logical to us that if encountering a constant flat rock wall in the direction they want to dig, animals would give up.
So, brilliant idea in mind, I went looking to see if there was any information on how this had been done before. My first warning sign was that there was no such information to be found anywhere. Finding this a bit odd, I then went looking to see if anyone had done it with concrete. The only information I found about protecting chickens with concrete underground had been having them live on slab which we don't want to do.
Initial research done, I went and talked to a local who has been of great help to us with everything since we moved in. So far his advice has been good, and seeing his family chickens was a big inspiration to my lady. When I brought it up to him, he immediately explained that I didn't want to do that.
Apparently I just don't know how to think like a wild animal, and I need to be able to do so to plan how to deal with them he informed me. I protested that there is no way that even the strongest animal would be able to dig through solid rock, or even slip through two rocks that were overlapping I was thinking of doing slab rocks.
His explanation was approximately thus. When you bury a chicken wire fence around here, you do so with 2 feet down, and a 2 foot apron or there about. When the digging pests around here encounter said fence they try to dig down and go under it. They follow the line of the fence, and when they reach the apron parallel to the ground, they get frustrated. The fence isn't solid, but they still can't dig through it. Because of the not solid but can't get through they get frustrated. If they encounter a flat rock wall, they know what to do. Again, they dig down to get under the wall. When they encounter the apron though they know what to do, they follow the surface of the rock, find its lip, go down the lip and follow the underside of the rock until they find the other side and come up. Unlike fences they encounter rocks in their day to day life, and rocks provide a piece of a dug hole that they know wont fall in on them.
This particular potential issue hadn't even crossed my mind. Sadly it makes complete sense to me that animals used to living and digging in rocky hills would know how to deal with their constant nemesis, rock. I figure it's kind of like building roads, it's easy to deal with a solid obstacle, something that constantly shifts would be a problem.
I am going to do a bit more checking because it is a bit disappointing that our idea is apparently not workable. However it seems fairly likely that the reason I've never read about it is there is a reason it isn't done. That is the problem with brilliant ideas, in something like homesteading people have been doing all of the tasks that make it up for centuries. Generally in those centuries if there is a natural free material that can be used, it will have been tried. I'm not saying don't look for creative ways to solve problems, but as with everything else I say, do your research.