What is happening to the chickens?

 The day before yesterday I found feathers in the yard. Now chickens lose feathers all the time especially when they are, but to have that many in one place usually means something happened.  I counted and one was missing so either something happened, or she went to sitting, but with all those feather I am betting on the first.  It has been a couple of days and she is still missing. It is kinda strange because if she was got at night then the feathers are usually under the tree she roost in but the feathers were between the house and the garden. Plus we have four dogs, they don't usually let anything in the yard.  It could have been a hawk.

Yesterday evening my husband brought home some turkey eggs.  While cutting hay he ran over a nest and the hen was killed.  We usually either hatch the eggs in an incubator or under a hen.  I had one hen sitting that had lost 2 other nest but was trying for number 3.  We were going to put the eggs under her this morning because both her eggs and the turkeys were about at the same point in development. I went out this morning and she is gone. Her nest is destroyed and feathers everywhere.  Still the dogs didn't bark. This time I know it wasn't a hawk. I am beginning to think it is one of our dogs. I am going to set up one of those game cameras to find out.  We now have only 3 laying hens.