The 1st video wasn't a hawk video. The 2nd video showed the hawk preferring to use his wings as much as possible but too many obstacles & no success hunting. Which to me affirms their need to catch prey in flight w/ plenty of air space for successfully using talons to grasp prey. A Cooper's flew after a Mourning Dove & the dove flew inside a neighbor's banana tree & the Cooper's didn't go into the tree after it though it was easy enough to extract.Coopers are good fliers, but DO hunt 'close'
Hunting in a brush pile
Hunting Squirrels
Info on their life and hunting style
I truly suspect that the Coopers hawk in your area have found easier prey or are bothered by your presence or something else. It really doesn't seem like your set-up would preclude them from getting your Silkies if they were hungry enough.
14 yrs of obstructed air space & non-friendly thick trees, patio roofs, dog houses, benches, lawn furniture, popup canopies, etc, have worked for us so far. Nothing is ever 100% where predators are involved but as chickeneers we do our best to figure what has worked in our own environments.
I think our nearby Santa Fe Park & our nearby mountains/meadows offer hawks more easy flight space than our obstructed neighborhood. We seem to get the inexperienced Spring fledglings around here that look confused as to what they're supposed to do when perched atop a roof or telephone pole. I guess the parents or Crows eventually chase them off to find their own territory to patrol cuz we don't see them in summer, fall, or winter ~ only a fledgling or two in Spring.
I've shared before that one fledgling flew straight into our dog kennel wire chicken run & knocked itself out! That's when I didn't mind that we had over-spent on our Fort Knox coop/run setup! Still not all safety measures are 100%. For instance, it's a bit absurd to try & electrify a block wall from predators ~ anyway we wouldn't want to deter our favourite neighborhood rat hunters ~ cats who walk on the wall.
Lots of things to take into account what predators are in an area. My #1 complaint is still the stray dogs or inconsiderate neighbor that lets their pup run around loose pooping on lawns or barking at cars or pedestrians ~ or the smaller loose Chihuahua mixes trying to squeeze thru our gates!