Please read the article below.
MISTAKES TO AVOID IN ORDER TO SUCCEED IN THE POULTRY BUSINESS
From my experience there are a few things you need to ensure:
-A proper housing structure that ensures the birds (especially chicks) do not get too cold in the evenings and that they are secure
-Following the vaccination schedule
-Buying chicks from a quality source
-Giving the proper feeds that meet all nutritional components
-Following proper biosecurity measures on the farm