Re:India's farmed chickens dosed with world's strongest anti...
by maxerickson on Friday February 02, 2018 @12:13PM
(#16292191)
In cattle, certain antibiotics shift the composition of the bacteria in their digestive system and help them better deal with corn heavy feed (both extracting more energy from the feed and also mitigating illnesses due to the feed mix).
http://edis.ifas.ufl.edu/an285
There is also other growth promotion due to antibiotics.