As sunlight has a good effect on horses, we should secure a sunny aspect for the stable and have it well lighted by windows. When the horses are at work, it is a great advantage to be able to open out the stable, so that it may be disinfected by sunlight as well as by fresh air. In our desire for sunlight, we must not obtain it at the cost of raising the temperature of the stable, which we would do by having the roof made more or less of glass. In the case of animals which, like racehorses, do their work in the morning and will want a rest in the middle of the day, it is advisable to have an arrangement for darkening the boxes or stalls, while shutting out the fresh air as little as possible.

I like to have the divisions of the boxes and stalls and the interior of the walls of a light colour, if not actually white, so that there may be but little loss of sunlight. It has been stated that the effect of having a white wall constantly in front of a horse while he was in a stable, would be injurious to his eyes; but I have never known or heard of a horse suffering from that alleged cause. The same may be said of human beings, many of whom live the most of their lives in whitewashed rooms, without their sight being hurt by the supposed glare, which, in almost all cases, would be that of diffused, not direct sunlight. We should also bear in mind that the eyes of a horse, by the possession of corpora nigra (the dark-coloured and irregularly-shaped bodies that project more or less over the pupil of the eye), are specially adapted to enable the eyes to bear strong sunlight with impunity. The corpora nigra are portions of the iris, in which the pupil forms an opening.

It is an advantage to have the stable lighted, though dimly, at night, so that in case of alarm or necessity, the owner or groom may be able to see his way about the place, without having to delay in getting a light. We may be quite sure that the presence of the light can in no way disturb the horses; for when these animals are turned out, they get all the sleep they need; although, even on moonless and starless nights, there is as much light, if not more, than there would be in a stable when the gas or lamps were turned low down. Besides, the fact that many horses which kick or are otherwise restless when in a dark stable at night, will remain quiet if the place is somewhat lighted up, seems to show that horses do not like darkness, which in any case is an unnatural condition for them.

Precautions against fire are even more necessary in stables than in ordinary houses. In some luxurious stables each box is furnished with an electric burner.