I've noticed my Horsefield has a couple of small brown flaking patches on her shell as well as a slight green tint... is this shell rot? She also has some pitting on her top scutes which I thought were from overfeeding but now im worried it's all connected ?
If the depressions are what you are referring to as pitting, these appear to be very old scars. They may have happened when the tortoise was young from and injury, attack or as defects. They are nothing to worry about. The flaking or scaling could be from shell fungus or debris. Based on it's overall shell appearance this tortoise appears to be quite old and or have lived in a very harsh climate. It is not at all unusual for wild caught Russian tortoises to look like this. Commonly known as shell rot, it can be caused when there is an injury to the scute allowing fungus or bacteria to get in between the scute and the bone of the shell. It will eventually cause the scute to deteriorate, break into pieces or come off completely. An active fungus can be soft under the infected area and have an odor. An older infected area where the fungus is no longer active will usually be hard but the bone may be deteriorated or scarred. If you feel that it is an active fungus you may want to have it checked out by a vet. In minor cases I have used betadine and triple biotic ointments with success. Most importantly, if it is an active fungus keep the area as clean and dry as possible until the problem is solved.
Is this something new for this tortoise?
Or did you receive him this way?
That would be an extremely unlikely place to see a fungal issue.
It's also unusual for a Russian (Horsefield) to have any fungal issues.
To me, it seems more likely that it could be an overhead burn from a heat source too close to the tortoises shell. Or some other type of superficial damage.
There appear to be semi punctures similar to a dogs teeth marks there, also.
These are all speculative.
Is there a dog near the animal?
What type of lighting and heating are you providing?
As GBTortoises has already said, this is old shell damage and nothing to worry about. You can see, in the couple of smaller spots, that there is already new shell growing under that brown area. The larger brown shell will eventually pop off too and there will be new shell underneath.