Hi there, I am an entomologist and a chicken keeper. The insects in the photo are nymphs of one of the "true bugs" (suborder Heteroptera). Most of these insects feed on plants and are likely harmless to your chickens. They look like they have recently hatched, which explains why there are many of them in one place. A female may have found a nice sheltered spot on your coop to lay eggs. They will likely disperse on their own soon. I highly doubt they are causing any issues for your chickens, your chooks might even like them as a snack.
You could spray them with soapy water or Neem oil if you want to knock them back, but doing nothing is probably fine as well.