Gracie. Sweet Gracie. No you didn't hurt her with the meds. There just wasn't anything that was going to work for what really caused this.
As
@micstrachan pointed out, her cherry red comb and wattles indicated a spike in body temp and that the infection was running wild at that point, and it was then I knew we had probably lost her. This was just bigger than all of us to fight.
I am guessing this was a cancer with a secondary bacterial infection. There isn't much to be done for those foes, even when it hits humans.