I don't think lice/mites would affect her so quickly when her roomies are all fine.
The tail down is a big red flag - says to me egg bound or peritonitis, both of which need urgent care.
Is she pooping normally? When did she last lay?
Warm bath for half an hour, then somewhere warm & dark with food & water. & a heavy dose of calcium - break up a tums & put each bit in her beak so she swallows it.
Hopefully it's something less serious, but those measures won't hurt her no matter what's going on, & if it is egg binding it could save her. Good luck x
The tail down is a big red flag - says to me egg bound or peritonitis, both of which need urgent care.
Is she pooping normally? When did she last lay?
Warm bath for half an hour, then somewhere warm & dark with food & water. & a heavy dose of calcium - break up a tums & put each bit in her beak so she swallows it.
Hopefully it's something less serious, but those measures won't hurt her no matter what's going on, & if it is egg binding it could save her. Good luck x