One of my month old chicks chased a bug underneath a fence gate into my backyard and as I turned to get her, my dog jumped across an electric fence wire - which he NEVER has done before - and snatched up my baby chicken. I screamed at him and he immediately dropped her. The chicken ran back under the gate and stood there gasping for air. I thought she was simply traumatized. Babied her, held her, petted her, rocked her to sleep etc. Kept separated, but in a wire cage sitting next to the coop where she could see the others. She was eating and drinking fine. That night I noticed she was not with the others who were perching so I brought her inside and held her again. She relaxed and slept. Couple days later she started sneezing and gasping. No vet available. Internet search suggested respiratory issue. Gave her cephalexin with her food and brought her inside overnight. In the morning, fine again, trying to get out of her box. Took her outside and she was pecking at bugs but then started sneezing/coughing again. Brought her inside. She was really struggling to breathe this time and although I found a vet, he recommended that I continue with the antibiotic and add electrolytes. He honestly didn’t sound hopeful. While I was holding her she stopped breathing, struggled and kicked, then died. It was horrible. She had NO visible injury after the dog dropped her. Eyes clear, poop normal, eating and drinking up until the last hour. At times sounded congested in her nose, but when I held her and calmed her, breathing was clear. I cannot stop feeling sick to my stomach and need to know what I missed. Obviously the dog should not have gotten her. It happened in less than two seconds and I was standing there the whole time. The dog did not deliberately injure the chicken but I feel like that incident was related to her death. None of the others are sick. Please give me ideas, but you don’t need to beat me up, trust me. I’ve been beating myself up for two days now. There was nothing visibly/externally wrong with this bird.