What happened to my elder brother always open his mouth

My elder brother often opens his mouth to heat the heat.In summer, it is usually kept in a place of avoiding light, while maintaining good ventilation.Let it take a shower once a day so that you can keep your body clean, and at the same time, it can also cool down.Because the high temperature will cause the feed to be rotten, it needs to be replaced every day, and the leftovers that are not eaten are dumped, and new materials are added to it.In addition, the cage should be cleaned regularly to maintain environmental hygiene.