Same with me. I was really against it for a while. Now I'm not so sure. This summer I came upon a vet's PhD dissertation on increasing animal welfare for the process of culling battery hens. This concerned the situation in France and most of it was about the stress the hens underwent during handling , transportations and waiting to be culled (lasting for as long as three days, packed and starving). So it's a terrible ending after a life of pain. Rescues in France represent about 1% of all ex-batt's. I saw that BWHT claims to put 50 000 rescues for adoption each year, I'm not sure how much that represents. Anyway I thought rescue was in a way supporting the system but with numbers so low, I'm not so sure.
For now the proposal has been rejected, but there is a huge concern toward antibioresistance developing and whereas the use of antibiotics for livestock is declining in European countries it is really increasing for domestic animals.
A list of antibiotics have been dedicated for human use, and others are on a watchlist where the vet has to declare any prescription.
I know we don't have alternatives to treat pets, but if the antibiotics stop working we will have the same problem.
E. coli is one of the most concerning bacteria for antibioresistance and one that affect chickens often.
I don't think a complete ban for vet use would pass, but I do believe restrictions will get more and more drastic. Same for antimicrobials.