getting under thrivers to grow, and grow dramatically.
We have taken in about 10 underthrivers from age 7 months to age 2 years, they had not grown or hardly grown any in months. Immediately they started growing and gaining weigth, some had poor husbandry, but some also had excellent care with good supplements. All were physically healthy, no MBD, no poor bone development. A density test did show that somes bones were not as thick as they should be
Were are still not sure what it is that is sparking that growth and bone thickening, but I think it is a combination of things and one for the key one is the light intensity which in turn increases their appetite. Also is the UVB from the sun and bright lights.
Their homes are in reptariums on a lanai(for ya northern folks that a screen porch with vinyl windows that open up to 3/4ths airflow). Early in the morning they have household bulb heat with director lights, and have salads/veggies. Around 10 AM they go outside in reptariums in full sun with a small amount of shaded area and small pools in thier enclosures. 2 PM they get pellets added, around 3-4 PM the littler ones get crickets and around 5 PM they are all brought back inside and given crickets at 6-7PM then back under the director bulbs until lights out and bed. We do not have these under UVB lights inside, they are getting pleanty from the natural sunlight, if it is a cloudy or rainy day they do get UVB lights.
Now the sunlight in Florida is very bright/intense, so is their director lights inside, they all have places to hide, but only a few do and those few are the slower growers. The ones staying in full sunlight and household lights are growing much faster.
We also decided to raise the imported babies in natural sun light, and we know that the ones receiving more full sun during the day were the faster growers, (the others were in partial shade from the other reptariums).
We were just not sure if it was the UVB from the natural sun or the light intensity from the brighness that is sparking the growth. So we took one small one and brought her inside under UVB MV lights and additional light intensity, so she is getting less UBV than the others, but at least the same or more light intensity, she has outgrown all the others now that were the same weight and length as her. Another one we put under no UVB, good supplements and lower brightness, she ceased to gain weight or grown any for 2-3 weeks, we added brighter lights and she again started gaining weight, slow pace, but gainingfor two weeks. We added the UVB back with MV and she starting increasing in weight more over the next 2 weeks and gained back to the size of the others.
My conclusion, the light intensity is the greater effect on the growth. But the UVB is a factor also. It would be interesting to do a longer study with ongoing bone density with a clutch and and more control groups. I plan on doing that this spring.