Bless you for fostering!
I am so sorry the baby has lost her meow.She most likely has a sore throat.
All you need to do is give her a drop of honey every 4 hours. It will sooth her throat and return her meow.Most cats will lick it off your finger.
It is a remarkable healing agent:
Feed canned food till she gets her voice back.
However, keep a eye on her for any sneezing which would indicate an upper respiratory infection. These are viral,airbourn and very common in kittens.
Please let me know how she is doing.
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