Yes, the crows in our area appear healthy. However, last winter we had a crow with an injured foot.  You wouldn't know it was injured except he/she did not put any weight on it.  He was part of a family of 5 individuals.  I think they were the ones in the nest in our neighbor's tall white pine. The family did not nest in that site this year. Come to think of it I did not see much of them beginning in March. A good number of years ago (maybe 7 or 8) my husband found a young crow on the ground who could not manipulate either of its feet. We kept an eye on it, but when the local fox came around, we set the crow on top of a yew bush where it was supported in the boughs. We were hoping to see the mother come to its assistance.  Unfortunately, the crow was deceased the next morning.  It was odd in that it did not look sick externally - no wounds.

Question 2.  I’ve never seen crows being aggressive with each other.  I have seen other types squabbling with each other - like Robins.

Q1. Yes the crows seem pretty healthy and spunky in my area. I haven’t noticed foot disease. I’m don’t know about West Nile impact in my area. However my birderfriend told me in his county many crows in his area died out from West Nile and that they have not recovered. He said that grackles seemed to have filled in the gaps the crows left behind.This is second hand info so I don’t directly have evidence of this.

I once noticed a crow walking on one foot due to an injury on his other foot. Now I understand so much more about foot disease in crows.