The addition of chlorogenic acid alleviated jejunum histopathological changes caused by CP type A infection in the jejunum of 17- and 21-day-old SPF chickens. The histological features of the jejunum mucosa in the control group, CP infection group, CA group, CA plus CP infection group (CA + CP), antibiotic group, and antibiotic plus CP group (antibiotic + CP) are shown together with the hematoxylin and eosin staining of 17- and 21-day-old SPF chickens. For histological observation, images at a lower magnification (100×) are provided. n = 9 chickens/group. Abbreviations: CA, chlorogenic acid; CP, Clostridium perfringens; SPF, specific-pathogen-free.