I have had people ask me over the years how I do one thing in particular. That is, how do I change the temps on one cage in a stack?
I have all my cage heater cords going up to the top of the stacks of cages except one bank that I have access to from the back of that wall of cages. This is a view of the back side of that wall.
Every singe cord is labeled so I know which cage each one goes to by simply looking at the tag that is attached to each cord. Those cords are labeled "1" for the bottom cage. "2" for the second cage up, etc. all the way up to "6" for the cage on the top of each stack. I run all the heaters on this wall with two Ranco thermostats. One thermostat is set at a good maintenance temperature. I run my room at 76 degrees and the 1X sized heaters at 87 degrees during the day time. I simply turn off the heat at night. The temps drop down to 80 or 81 overnight and only creep up to probably 84 or 85 before I turn them all off in early evening. This temperature works well for breeding and or any other time of the year for non-gravid males or females. Simple right? That's how I try to do things. Simply in a way that works and is both great for the animals and easy for me.
The second thermostat is my "GRAVID" thermostat. That thermostat is also set at 87 degrees year around until my first female ovulates and goes into a shed. I have one cage in the furthest stack in this picture, the fourth cage up, that is designated as the "GRAVID" cage. When I have the first female on this wall ovulate and go into a shed, I move her into this "GRAVID" cage. This is where she will remain at least until she gives birth. Once I have introduced that first gravid female into the "GRAVID" cage, I bump the temperature on the thermostat that is monitoring that cage, to 91 or 92 degrees. This allows that one cage to run warm enough for the proper gestation of those babies she is carrying. I use Aspen as a substraight. I also push all the Aspen off the heated area, so the female can have access to sit directly on top of the heat without any of the Aspen insulating the heat. This one cage temp being warmer does have a tiny bit of impact on both the cage above and the cage below, but not that much.
The image below shows the two power strips I have behind the stack with the "GRAVID" thermostat set up. The top strip is connected to the maintenance thermostat that is set always at 87 degrees. The lower power strip is connected to the "GRAVID" thermostat that is bumped up as soon as the first female ovulates. You can see there are two cords plugged into this strip. This is because I have it set up for two gravid girls in that stack.
This other pair of power strips shows all the cages are still plugged into the maintenance power strip indicating that nobody is yet gravid in that stack.
It's a very simple system that I have used for a long time to simply tweak each cage when the time is right. You can accomplish a lot using few thermostats with a bit of ingenuity. 
Here are some of the babies that were born on this wall of cages in 2011:
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Jeff Ronne Sr
The Boaphile
Director USARK
Originator of Boaphile Plastics
The Boaphile Boa Site
