here in common places they just call them zip ties with no specification. I don't know if in some specialized shops there are uv rated, etc. mine probably are chinese. they (black) last 3-5 years.
lucky you! I have to dismantle pallets with twisted nails. it slows me down. at least I have got a few "motorbike" pallets that have good, new and good size wood. duck nesting boxes are my project for them.
my albanian neighbor (from my old place) taught me to use a smaller box with some pillow filling to keep chicks warm at night. works great. as I had a lamp accident (luckily woke up on time) I prefer to avoid to use lamp when I sleep. also I find chicks less stressed when sleep at night.