The harware section (nails, fasteners) at either Home Depot or Lowes has nails which already have a plastic blue washer installed on it. They work great and no need to search for the correct size metal washer. You can get a box of a hundred or so and that should be enough.
I have an Ameracauna that for the past week has laid 2 eggs per day for 3 days. She's the only one laying eggs, (I have only 3 hens) so I know it is her. She's laid double yolks 3 times.
Here is what worked for me. I put a small photoelectric night light inside the coop. When it gets dark, the light turns on and the hens are attracted to the light. They go in every evening without failure.
I seen it on a thread here too about the frozen water, I use two gallon jugs, place them in the freezer at night, and put them in the chicken coop and run in the morning, no problems yet, today is forecasted to be 106 here in Central Texas.
Here's what worked for me. I placed a small night light with an optical sensor inside the coop. Without fail, every night, they go inside the coop towards the light. The small night light isn't too bright, but just enough to attract the birds into their sleeping quarters.
I'm in the process of building my coop and concerned about the hot Texas summers. I've considered installing insulation sheathing on the frame and then covering the exterior with T-111 siding, I'm wondering if the chickens will peck at the exposed insulation inside the coop. Should I install...