I LOST 3 CHICKENS IN 3 WEEKS

[Ute in UK]

Good Morning together,
we do have Wyandottes. We had till 3 weeks ago 7 hens and a cockerel.
3 weeks ago one died after being a day looking not well. then 2 weeks later another one was completely unexpected dead
in the coop. and this morning I see one other is going to die, she is curling up with her head in the feathers. She was absolutely
fine yesterday. the only thing I realize she does a kind "gurgle" like a dove. (only she did that)
They have been all only 2.5 or 3 years old.

What can that be, what can I do. Now I am down on 3 hens and the cockerel. I am so scared to lose also them.

Any advice, am very sad.

ute

 

[DobieLover]

Have you listened carefully for rattling when they breath? Especially at night when it's quieter and you can hear them better?
Do any of them have bubbles in the eyes?
Are they actively laying?
Have you done a thorough physical examination of them at night feeling for body condition and inspecting for external parasites? Checking inside their beaks?
Have you done a fecal float to check for internal parasites?
What is their poop like?
Are their crops full at night and empty in the mornings?