Yep, sure will given the chance. Had a friend say they had crows harassing their chicks outside and would have pulled them though the wire given the chance. They are in Seattle too.
We have many crows who mainly look to the feeder for a quick meal. My full grown chicken chases off our crows by charging them like a rhino. The crows did not bother with my pullets at 8 weeks plus although I would hesitate putting younger chicks out there with them. Someone told me (Nautical Buoy?) that the crows actually have a protective effect as they ward off larger aerial predators such as hawks, etc... This sounded feasible to me since they are such a nuisance to many other species of birds. However, i am no expert...just reporting my observations.
Crows will take any kind of egg, small bird or mammal. That's why the smalled wild birds hate them so.
We have so many crows this year! And they love to hang in my trees. And squirrels! Black one and brown ones. Yesterday I drove past our park and there was a black squirrel with a brown tail... actually kinda cute for a varmint.