Personally I wouldn't put any oils, even natural and organic stuff, on the shells of tortoises - on the basis that it only collects dust and clogs up the surface, and also that it isn't natural! If I want them to look shiny, or to show off their colours to a visitor, I might spray them with water - as long as they can dry off before bedtime.
As for feeding horsfields, beware of over-feeding. In the wild they're only active for about three months of the year, and range widely to find food in that time-slot. In captivity they'll continue to be opportunistic feeders, so it's easy for them to eat too much, and they're likely to be awake and feeding for more than three months per annum. I've got a rescued horsfeld that was clearly fed either too much of the right stuff, or possibly too much of the wrong stuff - calcium-deficient foodstuffs I would guess, and his carapace is consequently very distorted. Sad.
As for feeding horsfields, beware of over-feeding. In the wild they're only active for about three months of the year, and range widely to find food in that time-slot. In captivity they'll continue to be opportunistic feeders, so it's easy for them to eat too much, and they're likely to be awake and feeding for more than three months per annum. I've got a rescued horsfeld that was clearly fed either too much of the right stuff, or possibly too much of the wrong stuff - calcium-deficient foodstuffs I would guess, and his carapace is consequently very distorted. Sad.
