Man, you are an awesome bird daddy! Your questions - what's the point of calcium - if birds don't get enough calcium, it can cause it can cause a decrease in eggs, osteoporosis in the hen. It affects the development of a shell. Sometimes we'll see perfectly formed eggs with a thin shell or no shell at all. Lethargy, weakness in the hen from a deficiency, bc it's vital for muscle energy. Severe deficiency can lead to paralysis. Often we'll see feather-pecking, which can lead to cannibalism. Layer feed has additional calcium in it, but that should only be used during laying season, & then you have the issue of separate feed bowls, bc excess calcium causes kidney issues in the boys. That's why many just offer the calcium grit.
Salpingitis. - I've not dealt w/that, but it does explains everything. Meloxicam is used off label sometimes to reduce pain & inflammation. Disturbing, but informative article
https://the-chicken-chick.com/salpingitis-lash-eggs-in-backyard/