No,Coccidiosis is always around,spread by birds,bringing it into your flock from new chickens,clothes,shoes,hands,feed utensils,etc. Most birds have some cocci in their sml intestines,only becomes a problem when they have an overload/outbreak,then we medicate to bring it back under control. All chicken keepers should know the signs and symptoms of Cocci,medicate immediately. Medicated starter feed does not prevent cocci,chicks can still have an overload/outbreak. One of the biggest misconceptions about cocci,is that there has to be blood in poop,and that medicated feed prevents cocci,completely wrong. There are 9 strains of Cocci,and only 1 has blood as a symptom. Cocci thrives in warm/moist/damp conditions,ideal brooder habitat. Once chickens have cocci,it is then spread by their droppings,which get into feed/water via droppings. Chickens ONLY build immunity to the strains they have been exposed to.