I am making a large number (~50) birdhouses for installing on some vacant forested land that we have. Due to the sheer number of birdhouses that I am working on making, I am using low-quality cedar pickets normally used for fence making. They cost $2/picket compared to $10 to $15 for quality lumber, which makes the project affordable.
Anyways, I glue up the birdhouses using Titebond III wood glue and then install #8 exterior wood screws, as I have heard that the wood screw + glue combination will last longer. Unfortuantely, the cedar often splits a little as I install the screw.
My question is what should I do to protect the cedar split from the elements? My concern is that the split area will allow water instrusion and therefore will start to decay the wood faster in this location. The easiest way to protect the wood is to smear a little wood glue on the outside, but perhaps that isn't necessary?
I would like the birdhouses to last about 10 years outside. I'm staining them with fence stain to help protect them and might need to restain them in 5 years or so.
Below is a picture of the first 5 birdhouses.