moulting season; molting season
Refers to the period when animals shed and replace their fur, feathers, or skin. Used in biological, veterinary, and pet-care contexts.
During a rabbit's moulting season, a lot of fur comes out.
Brushing is essential for dogs during their shedding season.
Compound of 換毛 (かんもう, 'moulting/molting') + 期 (き, 'period/season'). 換毛 itself combines 換 (exchange/change) and 毛 (fur/hair).