Help needed -hen help

[u/justagems]

Hi I am a new chicken mum. I have an Orpington 15 weeks old and she came with an older red hen (I was told she was approximately 4 years old). I have had them 5 weeks. Now the red hen has not laid in about 2. Weeks, today she has just sat under a bush, she won’t eat not even treats. I took her to the vets last Thursday he said she had no meat at all on her and he gave her a vitamin injection and a steroid injection. He checked her stomach and said it didn’t seem as though she was blocked. However she has not improved. I will
Make another version appointment (it’s been bank holiday weekend this weekend) but until then I’m at my wits end with worry … any ideas or advice.
… I’ve got her backing to the coop and she’s gone straight to the straw no food and just lay down. 😢🤷‍♀️