Swans and other waterfowl must have non-abrasive substrates with zero entrance water features. Steep inclines can cause serious leg and foot injuries. The substrate can have no abrasive features (concrete, gravel, rocks, etc.), or the birds can develop a condition known as bumblefoot, a highly contagious staph infection.
Now, with this basic understanding of swan needs, there would be several concerns about using artificial grass:
1. Swans are grazers, meaning they eat grass. The swans will probably pick at the fake blades, not only tearing up the surface, but possibly eating the artificial material which would not be healthy. Eating the material could also cause choking.
2. Artificial turf can be prone to molds and fungus in extremely wet conditions. The substrate would need to be pressure washed or otherwise cleaned to keep the surface clean from bacteria (from swan poop), molds and fungi. Remember, waterfowl are prone to bumblefoot, so this surface would need frequent cleaning. The chemicals used to clean and prevent mold and fungi, may be toxic to the swans.
3. The artificial turf is a nylon woven material. Think of the rows of blades being interwoven in a netting type material. Swans have claws and the claws could become snagged in this netting material. We had a swan get its claw stuck in some temporary nylon fencing, and the claw was torn from the foot. Not good, and no one ever considered that a swan would get into the nylon fencing, much less sustain such an injury. Birds and animals do not behave in a manner that you would expect, therefore you have you to consider many possibilities for the chance of injury.
4. Even though swan pens and habitats do require much work to keep clean, the best substrates are soil, natural grass (although swans will eventually eat and turn to soil), or straw.
Due to the above reasons, we would strongly encourage the use of soil or more natural substrates, not artificial grass. The Regal Swan