Help! Chickens dying with no symptoms...down to one girl :-(

[Country bliss]

I had 4 Buff Orps, 1.5 yrs old. No history of illness. No recent changes in food or location (they lived in a chicken tractor on my property). So, about 3 weeks ago I found one of my girls dead in the nestbox. I thought she might have been egg bound. I palpated her abdomen and didn't feel anything. She was acting normally and eating/drinking normally. Two days ago I was awakened by the girls clucking loudly (my window was open) at 5:30am. I heard a loud thump and then loud flapping so my husband went to investigate. He found another chicken dead directly under the roost like she died and fell to the floor, scaring the other 2 girls. Just like before, no noticeable signs of distress or symptoms - feathers normal, no discharge from nostrils, clear eyes, normal poop, activity level normal, eating/drinking normally. And finally yesterday morning, I got up and immediately went to the tractor and found my 3rd chicken dead. I'm so sad and angry because I don't know what's wrong?! I am now down to 1 girl and she looks fine but I totally expect she will be dead soon too. She's all alone but I don't want to get more chickens until I know my girl is not contagious. What could I be dealing with when there is no symptoms??
RIP Ethyl, Gladys and Gertrude....

 

[Mac14]

I don't know too much about illnesses and stuff, but do you maybe have a neighbor that would want to harm them in any way? Being that there are no symptoms, I don't know what else to say, other than I'm sooo sorry something so confusing and devastating happened to you. Hang in there.

 

[chkn]

I know buffs don't do too well in the heat. You might want to use a few drops of Ivermectin to get rid of mites and worms. For a real wormer use Valbazan of course. I guess you should consider some toxin, even moldy feed.

 

[ten chicks]

How hot has it been and describe tractor set up(ventilation,etc). How long have you had your girls? Do they have access to fresh water daily? Do they have access to grit daily? Any indication of possible crop issues?

 

[Country bliss]

I live in a rural animal friendly neighborhood so I don't suspect foul play. I'm trying to hang there, thank-you.

 

[Country bliss]

I've had my girls since they were chicks. I live on Whidbey Island in Western WA and we don't get hot weather here. It's been in the upper 70's to maybe 80 degrees. The tractor has ventilation along the roof and the door is always open. They have lived in the tractor since they left the brooder spring 2013. I always have clean water available and they are on grass (tractor moved everyday). I don't know what "crop issues" look like. I feed them Purina Layena and give a little cracked corn and mealworms for treats.They scratch the grass and I put a pan of dirt for them to dust bathe.
I've never wormed...would there be symptoms of worms, like runny poop? Would that kill them?

BTW, my little girl (that's her name because she was smaller than the other 3 and has a high pitched coo) is still alive. I try to spend more time with her these days because she is alone. Not sure when or IF I should get her some companions.

 

[Country bliss]

This is the tractor that my husband built from plans we got through an extension office.

 

[Country bliss]

This is the tractor that my husband built from plans we got through an extension office.

 

[ten chicks]

Your tractor is lovely,but too small for 4 birds,consider adding a larger run to give them more room to move around. Did they all have normal looking poop? Do they have access to grit daily? Crop issues can be impacted or sour,to check for crop issues check crop at night should be full from eating all day,check in morning before eating,should be almost empty.

 

[aquagolda]

it could be heart failure