Hi, I allow my RF tortoise regular outdoor activities & roam with close supervision & natural sunlight as much as possible from an early stage of their lives. I find tortoises responded quite well to growth & weight gain & were never sick to my knowledge, My first red foot started out at weighing only 87g to now a year later of 850g despite still being raised at an indoor enclosure but getting at least minimum 4 days per week of outdoors sun & fun, of course the most ideal situation for tortoises is to be raised outdoors entirely but due to seasonal changes of some areas that doesn't permit.
