which predator could it be?

Last year I lost two grown chickens. One was injured and healed and died later. The other was missing for two months and then was found headless in the yard....body in tact. All feathers still on the bird.

This week four chicks have been taken. No signs of them when the first three went missing. Then yesterday the fourth was taken and there were some feathers at the base of the evergreen in my backyard. Upon closer inspection there were other chicken feathers too but I am not sure if they were from any of the babies. No other signs, no bodies to examine. Looks like some crow feathers at the base of the tree too. Do not know if it was another victim or like my husband thought the attacker. I have never heard of a crow as a predator to baby chicks but I don't know. The attacks were in broad daylight. The other four big chickens seem to be unharmed and totally unconcerned as they were not hiding at all but rather continued to free range. I have them on lock down anyway....any thoughts? Also I am not sure the birds from last fall have anything to do with the chicks I just put it in there because they all seem to disappear without a trace.....

 

I have my cat who was in the house all day and rarely ventures out. Very few feathers....maybe five small ones from i think the tail....

Everything is at the foot of the tree and even one small feather stuck to the tree trunk just at my eye level.