That is a very sick bird but without some lab tests we can't tell from pictures.
Where are you located? (climate)
What is the housing like? (size of ventilation, # of birds, bedding, confined or free range, etc.)
Age of bird? Breed? Feed?
thanks to reply
Dear
I am in Nigeria Lagos
my coop is good and has good ventilation
i am cleaning every day and keep dry some time clean with phenyl liquid..change the water every day and mix apple cider also on daily basis ..
this sick one keeps separate from others ..its eating small food. not like others ..
I just start to keep few small chicken like 60 -90 days old chicken .i am Not as professional,, it's just my mourning
please help me and tell what first Aid i can do ..
and please let me know should i give any vaccination for all..