This is not a problem caused by antibiotics. Is a problem of genetic nature that happens because broilers are inbreed for growing big and fast. The same birds in true range with plenty of food would face exactly the same problem, with or without antibiotics. They are too heavy and often tend to have cardiac diseases, but they live short lives and are delicious so they are the most sucessful bird in the planet.
On the other hand, we are a paradoxal species. Able to feel horrified by this, whereas happily petting our distorted-faced bulldogs, persian cats, caesarean born bullterriers, extra-dwarfed toy Yorkshires, ponies and toy mini pigs, without any trace of moral conflict...