URGENT! My 2.5 months old aseel chick's body turned blue and died within a couple of hours

[Paki-Aseel]

How old was the bird? Any symptoms other than the swollen feet and blue color?
Are you in Pakistan?

Yes im in pakistan and chicks are around 2.5-3 months old

 

[azygous]

It's a gruesome mystery. Good to hear you're up out of the reach of snakes. Do you still have the body? If so, can you find a lab to do a necropsy?

If you can't, you can cut her open yourself and examine what you see. It might give you a few clues. Also, if you take photos and post them here, there are a few people here that can help you interpret them. I know you want to find what is responsible due to the possibility of it having consequences for the rest of your flock.