Question about Persian kitten & food

My 5mos. old Sluggo seems to be having trouble w/soft food. I'm giving him Chicken Soup brand hard and soft food, but the soft food seems to be giving him diahrea. Would it just be the type of soft food or does he just have a sensitive stomach? My other kitty who's a manx mix has no problem with the soft food and LOVES it! Sluggo wants some too, but it's doing awful things to his digestive system. Any advice on what I should try? Thanks.

Try a simplier brand ... chn soup is very complicated ( imho) ... I would try natural balences venison and pea and sensible choice by royal canin... some of nutros are simple but try the other two first .. if it still doesnt improve try homeade