Yes, Cooper's will go after full-grown chickens.  They'll chase them 
down on foot often.  (Peregrines, like all falcons, most often take 
their prey in the air.)

A Cooper probably couldn't carry off a large, full-grown chicken, but 
they'd eat what they could while on the ground and then leave the 
carcass, or most of it.

Immature Goshawk is also a possibility, since they look very much like 
immature Cooper's.  The white on the tail tip is wider in a Coop (unless 
it's badly worn down), but can also be seen in a young Gos.  You say a 
"band of white," though, which makes me think it more likely was a Cooper.


On 11/23/2012 9:16 AM, Linda Lunna wrote:
> After reading a post from a few days ago and checking Sibley, I am thinking
> the attacking bird that we saw may have been a Cooper's Hawk because it had
> pronounced striping on tail--especially the underside and band of white at
> tip.  Estimate the bird to be about the size of a crow.
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