To prevent birds from getting sick, you need to preserve the beneficial bacteria in the intestinal wall, which means you need probiotics, and because the probiotic bacteria are living bacteria, you need to feed them and their feed is the prebiotic because you have to use both. And synebiotic together if you use it regularly, you will not need to use antibiotics.
And Probiotic bacteria fight harmful bacteria by sticking to the intestinal wall, preventing harmful bacteria from sticking to the mucous membrane of the intestinal wall, supporting and strengthening the mucous membrane of the intestine, increasing immunity, and preventing gastrointestinal disturbances such as bowel infections, gastrointestinal diarrhea and diarrhea as a result of antibiotics.