To clarify my question: I have a neighbor with eight chickens two of which belong to another neighbor who looks after the chickens for two days a week when the others are in the city.
I spoke with the 2nd neighbor on Sunday and asked about predators and he told me that they had lost one chicken to a raccoon who "dug underneath the HC". When I asked for clarification he told me that they had an apron and had switched to HC cloth on the floor of the run (elevated coop inside) that was the covered with straw,
I had visited during the winter to see their coop/run setup and to have a discussion about their experiences. I noted that the coop was heated with a heat lamp clamped to a rafter and the coop itself was tight for eights birds (guessing 6' by 4' and perhaps 4' tall).
In discussion I brought up the topic of DLM as the lady has commented on their need to clean out the run on a regular basis, she had never heard of it.
We have a wide variety of predators around (fox, coyote, wolves, fisher, otter, weasel, mink, raccoons, the occasional dog allowed to run free and bear although there are enough houses around that they mostly stay away); I am building my coop and run area and have used BYC for information on design and predators, have never seen folks saying that raccoons will dig underneath an apron. Fortunately we appear not to have rats as the area is lake country with mostly modern houses and very little trash and/or decaying buildings.
I wanted to double check with the many experts that frequent this forum, very much appreciate your feedback.
It might be a question of semantics. What you are referring to as an apron and what is actually on her coop that the raccoon got under may be two different things. Also how far out from the coop/fence did it extend? If it was only a few inches perhaps something did dig under. Or perhaps everything was as it should be with the apron and it was a very smart and determined predator. There is only so much we can do in terms of construction to protect our flocks.