Weak chick PLEASE HELP

[SunnySideUp2026]

I have a 1-week old chick (her name is Cocoa) who hasn't been eating that well, yesterday and today. The day before yesterday, she had a blocked vent. Then a prolapsed vent. Yesterday, her sister died. We had to feed Cocoa and give her water ourselves yesterday, and today we're dealing with a blocked vent again. Any advice on weak chicks, blocked vents, and how to handle it would be great.
I'm new on BYC btw

 

[SunnySideUp2026]

She is also the smallest. Any advice is really appreciated! Me and my family are first-time chick parents, and I think we really need help!