Grass, soil, sand, concrete and stone have all been used successfully. It is recommended that animals have access to both hard and softer substrates in the range of enclosures to which they have access. If sand or other loose substrates are used, avoid feeding directly on these as this may promote accidental ingestion of the substrate and subsequent digestive problems. If grass or soil is used it should be taken into account that this surface may not be suitable when very wet or cold and an outside area with a suitable all weather surface should be available. Sand or concrete aprons around houses, the fence line, gateways or other high use areas are recommended to prevent these areas becoming eroded and excessively muddy. When using an area for mixing of animals, make sure that the ground conditions provide a good footing and avoid waterlogged or very slippery surfaces.