Housing
There's No Place Like Home
A 20 gallon starter reptile tank is recommended for a baby dragon. They can grow into it happily and have plenty of room to run around. They are easily found at local pet stores. We suggest a 4ftx2ftx18inch enclosure for an adult dragon as this gives them lots of room to move around. Solid wall, front-opening enclosures are really the best for a bearded dragon. A dragon's natural reaction is to run from something overhead due to predatory birds, a human hand swooping into a top opening cage can scare a dragon. Coming from in front of them helps establish that you are not a predator and build's trust. Also covered sides and tops of enclosures help a dragon relax and have less stress when they know that things only come into their home from one direction. Always keep in mind all enclosures must be big enough to have a hot side and cool side of the cage, this is why vertical cages are not recommended.
If you use an open glass tank cover up all sides except for the front so your dragon is less stressed and more secure in his/her environment. You could just cover the sides with paper or something simple from around your home but you can also use cool nature backdrops found at pet stores or online like those from the National Geographic line, but don't put these inside the cage.
No Roommates
I always say that multiple dragons in one cage past 6 months old is never a good idea, and even before that there is no guarantee they won't fight. When they are hatchlings they get along ok, but as they grow they fight for food and basking space. Dragons really prefer to live alone and have all of the best basking spots and food for themselves. Their stacking behavior may look cute but it is the beginning of the dragons asserting themselves as the 'dominant' lizard in the habitat.
Misbehaving
Once a dragon hits 6 months of age (sooner if possible) it is best that they be housed alone, especially males. As male dragons grow into juveniles and sub-adults they will start getting their 'black beard' and will want to possess territory and be dominant. Any dragon in their space is an enemy and will be attacked, sometimes loss of limbs and tails will occur. When bites happen is also leaves a dragon is susceptible to infections and tail rot. Males past 6 months of age start to grow into their sexual maturity. Even domesticated males will violently defend their territory, food and possible mates in the area.
Once a dragon hits 6 months of age (sooner if possible) it is best that they be housed alone, especially males. As male dragons grow into juveniles and sub-adults they will start getting their 'black beard' and will want to possess territory and be dominant. Any dragon in their space is an enemy and will be attacked, sometimes loss of limbs and tails will occur. When bites happen is also leaves a dragon is susceptible to infections and tail rot. Males past 6 months of age start to grow into their sexual maturity. Even domesticated males will violently defend their territory, food and possible mates in the area.
Male adult dragons will fight it's their natural instinct (this images is from link)
Battle of the Sexes
Females and males living together past the hatchling stage is always a horrible idea. Mating will happen even if they are siblings which can cause babies with horrible birth defects. In my opinion dragons need to be separated by at least 5 generations or more in order to be paired. So unless you have the correct housing, lighting, substrate etc. and can afford to feed up to 150 baby dragon mouths (which a male and female can create from 1 mating) keep them apart at all costs. Not to mention once they have mated the male tends to no longer care to have the female in his space and will attack her and keep her from eating and basking. We only put our males and females together to mate, and when they are done we remove the female immediately.
Black Beards and Aggression- not just for the Boys
Two female dragons fighting trying to bite each other's tail photo is from link
Females housed with females can work under certain circumstances, but I still in no way recommend it. Especially not for beginners or for people who are not at home a good majority of the day to watch for fighting. Girls will also fight and bite tails and toes if they aren't getting enough food, if they are agitated or if they are gravid. They will still fight over the best basking spot and peck each other away from food. They can still be aggressive getting black chins, head bobbing and being territorial just like a male. They really prefer their own space. I have heard stories from people who housed 2 females together since they were tiny and then out of the blue when they are around 1 1/2 - 2 years old they start fighting. Females also get frisky in spring and they do not like the competition of other females possibly stealing a male's attention. A more serious separation that needs to occur when housing multiple females together is a gravid dragon. Gravid (or pregnant) female dragons are very cranky, territorial and protective. After about a week into a pregnancy you must get the gravid female into her own space so she does not harm another female that she could see as a possible threat to her eggs. This can cause injuries or make the female become egg bound. This is when a gravid female refuses to lay because she feels unsafe and the dragon holds in her eggs. This is a serious condition that not only causes egg death but it can also kill your dragon as sometimes surgery is the only option to remove the eggs.
Breeders vs. Pet Owners
I especially do not suggest multiple female housing for beginners or for people who are not at home a good majority of the day to watch for fighting like breeders are. We always house the males alone but the girls get to share their space. We have several different cages for separating girls who are not getting along well. Sometimes they get moody and get tired of certain other girls. They require constant attention to ensure that all of them are getting to eat and bask, we constantly have to check to to ensure no one is malnourished due to bullying. So for a pet owner I still suggest if you want more than one dragon, get more than one cage.
I especially do not suggest multiple female housing for beginners or for people who are not at home a good majority of the day to watch for fighting like breeders are. We always house the males alone but the girls get to share their space. We have several different cages for separating girls who are not getting along well. Sometimes they get moody and get tired of certain other girls. They require constant attention to ensure that all of them are getting to eat and bask, we constantly have to check to to ensure no one is malnourished due to bullying. So for a pet owner I still suggest if you want more than one dragon, get more than one cage.
You are My Best Friend
Many people say that their dragons like having a cage mate or that they seem to be lonely and need a friend to bond with. I would argue that you should instead let yourself be the number one bond in their life. Hold them for at least 15 minutes every day and shower them in affection. That is not to say on occasion they can't hang out with other dragons (again I suggest only females together) in the bath or basking outside (which does not guarantee they won't fight). I suggest putting yourself in the position of becoming the one thing your dragon's life they are most attached to.
Deadly Cage-Mates
NEVER UNDER ANY CIRCUMSTANCES house 2 dragons together that are not the same size! Bigger dragons will attempt to eat smaller ones, remember they are reptiles and act on instinct. Baby dragons are snacks and larger dragons will eventually attack a smaller one in its territory, either as food or just because they are irritated. Also dragons do NOT recognize their offspring. Please don't ever house 2 different size dragons together or dragons with their young.