Small Breed Rescue of Southern California
One of the most controversial subjects you might find around Bearded Dragons is substrate. Search the internet and you will find opinions supporting just about everything, and just as many not in support of just about everything. Most importantly, almost none of it contains enough context to support their opinions either way.
One argument you may hear frequently is this is the substrate they are on in the wild. The context that is misleading there is the captive enclosure size of lets say 6 square feet vs the wild range of a Bearded Dragon which is hundreds of square feet. Containing your dragons excrement to a few square feet in captivity for which they will always be in contact with poses biological, bacterial, and pathogen problems that spread out over the large wild habitat does not exhibit. This requires meticulous husbandry and frequent soil/sand replacement to be healthy. Secondarily, the san and soil available in North America is very different than that of Australia. North American white sand is high in calcium carbonate which can neutralize stomach acid or quartz which can irritate a dragons bowels. Australian sand is some of the oldest on earth and it is heavily broken down mantle that consists of high concentrations of gypsum or lime.
Another common argument is impaction associated with any loose substrate including soil/sand. The context often missed here is the natural Bearded Dragon behavior of intentionally ingesting sand when they feel they are calcium deficient. Most bearded dragon impaction comes from poor calcium supplement or poor feeding practices more than it does substrate choice. If you provide adequate calcium then a dragon tends not to eat substrate intentionally. Poor feeding practices ranges from keeping baby/juvenile dragons on loose substrate since they often ingest lots of substrate learning to feed, and of course feeding on substrate that can be accidentally ingested stuck to the food.
One of the last big concerns with bearded dragons is respiratory issues. Substrates that hold too much humidity not only become a breeding ground for bacteria, fungus, and pathogens but also contribute to respiratory conditions that are often fatal to dragons. Dragons are from an arid environment and do not do well with humidity. Substrates with fine particulate dust can also contribute to respiratory issues in addition to eye irritation.
As a responsible rescue we need to take in both the needs of a bearded dragon and apply husbandry that supports ease and upkeep by all adopters, not just the most extreme herp. We need to assess the size of an enclosure, the fecal contamination, the age of the animal, and the traits/health of that specific animal.
Juvenile (under 1 year) / Handicapped / Sick Dragons:
We recommend not using any loose substrate at all for young, handicapped, or sick dragons. Young dragons are clumsy eaters and often will try eating substrate just to see if its edible. Handicapped dragons that are missing limbs or otherwise impaired need all the help they can get to move around the enclosure, and sick dragons should avoid anything that might complicate recovery so maintain as sanitary conditions as possible.
Adult Healthy Dragons:
For the majority or people we recommended P.J. Murphy Sani-Chips. They are sanitized scent free, dust free, highly absorbent ultra small particle blend of aspen, beech, birch and maple. Liquid excrement is quickly absorbed, it facilitates quick spot cleaning, the texture is soft making it comfortable to sleep on, and the particles are small enough that if ingested in small amounts will pass through safely. This substrate is the easiest to maintain and most cost effective for your average animal keeper where spot cleaning alone can easily maintain a biologically clean substrate between complete substrate replacements.
One complication to all of this is your specific dragon. If you have a dragon that just cant stop eating his substrate, then you should move to no substrate or slate tile. If you have a massive enclosure of 100 square feet, then some of the san/soil complications above may not be as much of a problem as fecal density is distributed over a much wider area and not condensed down to the unavoidable daily living quarters. As we stated in the beginning, context has a big affect on what substrate is good, which ones are not so good, and which ones should be avoided all together.