I wanna say new hamp... but they are a bit too light for that..
and the very bottom picture... the left one is a boy :/ so I think that's the darker one correct?
I agree with aart, worms aren't the first thung the his worry about. Look at them for mites and check the higher food etc. Do thehioheirhey have enough oyester shells/grit? Do you see mites? What kind of food are they eating?
X2 althought depending on the roosters temperment, 4 could be fine for him. I work at a chicken shop and we've got many many pens of a rooster with 1-4 hens. It all just depends if he's a Horny boy or not.
Go out just before sun down and put them in instead of waiting until dark. They can't see after the sun goes down, so they don't know where you are placing them.
This is pretty darn severe.. I've always used WD40 but that was always for a lot less severe than this. Im nit sure if it'll hurt the bird if you use it this late in infestation.
Chicks will eat anything. The shaving are large enough for it to be hard for them. Make sure you do NOT use any form or straw, grass clippings, etc because it'll get stuck in their crop, killing them. Shavings have always been the best for chicks since it's more safe and it's easily changed out
You should probably get her a friend or two. Chickens are NOT solitary and are quite social animals. I recommend getting two in case one dies for whatever reason. I'm sorry to hear about your hens
With juvenile chickens from 8-16 weeKS of age, you should feed them a grower (or flock raiser) feed. Layer feed can hurt them when they get older because is has too much calcium in it.
Scratch and other treats should be limited to about 20% of their diet because to them, it's like candy or ice...