Efficacy of

(1) Background: Various studies on artemisinin and its derivatives have shown that Artemisia annua may be of therapeutic interest for different diseases, including chicken coccidiosis. This study aimed to evaluate the effects of Artemisia annua on farm-reared broiler chickens by analyzing both the anticoccidial efficacy and its effect on the intestinal microbiota of poultry. (2) Methods: The experiment was performed within three houses on a broiler chicken farm located in Romania. House 1 was the experimental group and received a diet with an addition of A. annua. Houses 2 and 4 were the control groups and received anticoccidials. The prophylactic efficacy of A. annua against coccidiosis was evaluated by recording the weight gain, feed conversion rate, number of oocysts per gram of feces, lesion score, and mortality rate. (3) Results: The chickens fed with A. annua showed a decreasing trend in the number of oocysts per gram of faeces, and their lesion score was 80% lower than in the control group. The weight gains of the chickens treated with A. annua was lower, whilst the feed conversion rate was better than in controls. (4) Conclusions: Artemisia annua showed promising results in the prophylaxis of coccidiosis. Overall, the broiler chickens that received A. annua presented promising zootechnical performances and medical data related to coccidiosis and gut microbiota.