Is there any point in giving probiotics at the same time as antibiotics? And, will apple cider vineg

I've always wondered if it is just a waste to take probiotics while on antibiotics - I would think the probiotics would just die soon after they are ingested since the antibiotics are already in the hen's - or my system for that matter.

I've also wondered about ACV - will the acidity interfere with the antibiotic in any way? I figure I should wait until they/Ive taken the full course - and then start in on the probiotics and ACV. Any thought on the matter?
Thanks!
Amy