Red Dorking- Pullet went 2 months ago, Cockerel just went today

[CGilbert]

2 months ago, a few weeks after putting the Red Dorking trio into the large coop, one of the girls randomly died. It wasn't too cold, and definitely wasn't too hot. There was no signs of struggle or sickness. Of course this was a day after introducing a new chicken to the coop, so I chalked it up to that and put that bird into quarantine (All of my birds I only get from 2 people, so I had had birds from the same person before). This morning, my Red Dorking cockerel was found dead on the floor of the coop. There was a minimal amount of thin yellowish liquid coming from the nose and eyes, but other than that, no puncture wounds, no signs of struggle.
I am looking into Necropsies, but in the North Idaho area, there is no one nearby that is free or inexpensive.

Tonight, I went out to close up the coop and 3 out of the 5 birds left were sitting on the floor instead of roosting on their roost like normal.

Anyone have any ideas?

 

[cafarmgirl]

Since there is a history of new birds being introduced it certainly wouldn't hurt to run a course of Corid so you can at least rule out the possibility of coccidiosis. New birds can bring along a strain of cocci that is new to the existing flock and that they are not resistant to.