The ethical side of it is a issue, but as you stated probably a issue for another time.
I feel very fortunate that we have the option here to get free range chicken for myself and my baby
Is there anyway to check if perhaps your countries agriculture department also follows some sort of guidelines when it comes to weaning the chooks off the antibiotics before slaughter? I know you said that they don't monitor it very closely but perhaps you could do a search around.
Is there anyway you could order online from another country the canned food required or is that too much red tape (I honestly don't know anything about it).
At the end of the day if you are unable to find out the details of the type of antibiotics or if they are still in the system with the slaughter and are unable to order online any food I would probably say go with the canned food in your area still.
Cats have lived 15 years off dry food, it's not optimal and really it comes down to a personal preference. Do you think there is a greater risk of antibiotic resistance and sickness or is there a greater risk of bad food (and not sure how bad it is so assuming again) not being entirely species appropriate and causing some health issues down the track.
From what I have read the human antibiotics that are used in cats are Amoxyicillian, Tetracycline and Ampicillin.
I don't know how much that info helps you though but whatever you do decide to do I am sure it is with the best intentions and love for your babies so don't feel guilty.
EDIT: Just because the cats CAN live off terrible food for a long time doesn't mean it is healthy, just stating that it does happen.