Cat grass can be fed once a day during the moulting period. Cat grass is best fed once every three days during the non-molting period, and no more than three times a week. Cats shed more hair during moulting and eat more hair. They need cat grass to help digest and expel hair. During the non-moulting period, you don’t need to feed too much to avoid irritating the gastrointestinal tract and causing diarrhea, vomiting, etc. In this case, feed about ten pieces of cat grass each time.