The size of your dragon at a certain age is going to vary greatly by the type of dragons the parents were and there size. It seems to us certain dragons and lines that are around have a tendency to be smaller dragons and therefore their offspring are smaller longer then other lines out there.
Having said that, barely 6" at 2 months old to me is extremely small. To give you an idea... our dragons hatch out of the egg at anywhere between 3.5" on the small side to 5" on the very large side.. most have been right around 4.25" or 4.5". That is right out of the egg. With a proper feeding schedule our dragons reach 6" easily by 4 weeks of age, many by 3 weeks of age. The parents of our dragons are however 450g to 650g each which helps produce larger dragons.
I would def increase the feeding schedule of your dragon. At 2 months and barely 6 inches either that dragon was the "runt" of the litter, bred from small dragons, or possibley not fed properly for a variety of reasons (not blaming the breeder).
A lot of times a few dragons in each clutch will not grow well when raised with other dragons. There is nothing wrong with the dragon except it just doesn't like to be around other dragons and gets intimidated.. so the other dragons eat most of the food and the "smaller" dragon does not eat right and is stressed out.
This occasionally happens to us and we remove the dragon to it's own cage and within a few days the dragon responds incredibly and eats very good and grows normally and hits a nice growth spurt. So there are a lot of factors that can attribute to it being small.
As far as greens, our opinion is they should be offered greens from the time they are a few days old and are eating crix. The younger they are introduced to eating greens the earlier they will start.. not always, but it's a good rule of thumb. Most of our dragons eat greens and pellets by two weeks of age.. some sooner, some hardly ever eat them. I would def offer him lots of greens and veggies at 2 months of age.
brandon
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Dragons by Nature