A cat's hen-like squatting posture in the summer doesn't necessarily mean it's sick. While a hen-like squatting posture in cats can sometimes be due to illness or discomfort, it could also be for other reasons, such as relaxation, warmth, or alertness.
In summer, although temperatures are high, cats may still feel cold due to excessively low indoor air conditioning or cool, shady areas, and thus adopt a hen-like squatting posture to keep warm. Furthermore, cats may also squat like a hen when they feel comfortable and relaxed, which does not necessarily indicate that they are sick.
