I would try what
@azygous has recommended or if possible, reconsult your vet.
You mention you had 2 hens treated within the last 6 weeks - what for - Coccidiosis and Salpingitis? With what - Amprolium and an antibiotic?
I'd hazard a guess that the material you found is lash material, but could be wrong. Since you mention Salpingitis it's a very good possibility. Antibiotics can help fight the infection and inflammation of Salpingitis, but it is usually chronic and may require repeated supportive care and/or treatment throughout the hen's lifetime.