Hey there,
So sorry for your losses. My chickens are beloved pets, so I totally get where you're coming from. I'll be devastated when something happens to mine eventually, even if it's old age.
Now, I'm just throwing this out there, but since you're a vet you'd have much easier access than the rest of us, so you might use that to your advantage. Hens that have chronic reproductive problems can be given hormone implants to stop they from laying eggs. Might this be a useful option for the rest of your girls? I'd have mine spayed all together if it wasn't so dangerous for them (and bank-breaking for me). I think the implants are the next best thing. You won't have eggs anymore, but if they're not laying they can't lay internally or anything either I don't think. I don't know if it would help with reproductive tract infections. Maybe you could answer that for me actually?