Found a dead chicken today, don't know what happened

Hey All,
I've successfully been keeping chickens for a year and a half.   I have a small flock of chickens 5 hens and a rooster, now 4 hens...  I went out to the run this afternoon and found a dead bird.  There were no signs of trauma or predation.  We have snow on the ground and I looked around the run and found no predator tracks.  

Over the past few weeks I noticed she would hang out by herself away from the flock, at times but not all the time.  Aside from that she seemed normal.  I didn't see any evidence of mites or anything like that.  I last cleaned the coop Thanksgiving weekend; about a month ago.  

I noticed some bright green poops in the snow, I've never seen that before.  I gave them some red cabbage yesterday, not sure if it's related.  Aside from that I feed them a layer feed and give them a handful of mealworms each day.   And each morning I give them fermented wheat, oats and sunflowers.  

I read up on Marek's disease but I'm not sure.  Heart attack?  Egg bound?  Bird Flu?

I want to keep my birds happy and healthy, I feel like a failure.  How can I ensure the health of my remaining birds?

Thanks for reading!
Rich

My condolences. I’ve been keeping chickens for about 8 years now, and well, sometimes there’s just something wrong and they die. You may get more information via necropsy. I’ve found tumors and one bird that had a weird disorder causing giant fat deposits all over her internal cavity. If the other chickens are acting normal, I wouldn’t worry about it being anything contagious. She was probably acting oddly before her death because she was feeling very bad - chickens, like many animals, will hide illness and injury as best they can, until they just can’t anymore.

Chickens seem ephemeral to me. Most come and go quickly. A few hang on for a long time.

This happened to me with Rhode Island Red. No sign of disease, nothing wrong with the other birds, just one hen acting "off". When I went to inspect her, she just died in my arms. Turned out to be water-filled cysts when I did a bit of an autopsy. As I recall, this just happens sometimes and you can't do anything to prevent it. Her sister birds are all still living along just fine, getting well past their egg laying years.

All you can do when you see a bird acting off is inspect for any external symptoms, keep an eye on them, and maybe isolate if they're getting picked on. You did all you could. Sorry this is frustrating, I know!

a member on my site tried this a week ago... and was chuffed    https://www.youtube.com/watch?v=b37eUNn_3As

Generally accepted statistic for chickens is up to 5% loss rate per year. This is what is considered normal and completely acceptable, as in if you lose 1 in 20 chickens per year you are doing everything right. Sometimes you will know what happened, sometimes you won't.

Others have already suggested some important concepts - isolate as soon as you notice something off. This allows you to monitor food and water intake and whether or not it is eggbound and also allows you to inspect their stools with certainty that it was them that laid it. It seems like you will do your best to understand why it happened, which will make you a better than average chicken keeper already. Kudos to you, and good luck in the future. Don't take this loss personally, these things happen even under the best of circumstances.

Whatever they eat is immensely important, of course. If I could make a few suggestions:

1. Layer feed is a bad idea in most cases, because it is formulated for hens who lay DAILY. The all-flock feed is formulated for flock members that don't lay at all. The difference is: the layer feed has 4 times the amount of calcium of all-flock feed. So... a quarter of the calcium in layer feed goes to general body maintenance and three quarters of the calcium goes to egg production needs, but it's meant for hens who lay everyday. So, a hen who lays every other day needs only half of that, so for her 37.5% of the calcium in her layer feed is poison. For the rooster 75% of the calcium is poison. Not mincing words, because with all these micronutrients, we need to be careful- too little and we're dead (us and our animals), too much and we're just as dead. The body can adapt to some extent, by not absorbing all the extra, but receiving daily an exaggerated amount is an unrelenting assault... They develop gout in their feet, so many cases I've seen on the internet, the feet of older hens getting swollen and red, must be so painful too. The roosters just die extremely early.
The layer feed is very practical though for people who want to keep only hens of the specific breeds and age who actually do lay daily.
If you switch them to all-flock feed, you'll need to make available, separately, a source of calcium for the layers, like their own eggshells. They'll take as much as they need. But if you give away some of their eggs, then what? Best to have a second source of calcium available, besides the eggshells. The worry will switch from "Am I poisoning them with too much calcium?" to "Am I providing them with all the calcium they need?"  

2. The commercial feed is a good base but is lacking in terms of phytochemicals, which are the plant chemicals that have disease preventive properties. For example- quercetin, glutathione, lutein, lycopene, beta-carotene, capsaicin, resveratrol, etc. So, I think the extras provided shouldn't generally be more grains and seeds (which are not rich in  phytochemicals) but vegetables, fruits, herbs. Oregano is particularly good for keeping chickens healthy. Chicken poop is an excellent fertilizer, it makes gardening easier...