I do not recommend keeping Thh and Thb together mainly because I am fully against cross-breeding and hybridizing. We are just barley sratching the surface with getting people to understand the difference between Hermann's tortoises but many are still buying Thb thinking they are getting Thh. The two subspecies very easily breed with each other and for years a few breeders have been offering these cross-breeds as pure Thh. This ruins the bloodline and fertility rates drop significantly.

Other reasons are:
Testudo hermanni hermanni males are known to be quite agressive. Even though many are very small, they ram constantly and inflict nasty bites on cage mates both males and females. Here is the link to a video I have posted where a Thh and Thb of mine battle and they were only just introduced to each other:
http://www.youtube.com/watch?v=fyUstgg3YHY

Testudo hermanni hermanni are more susceptible to diseases and at times may not be as hardy as Thb. This is a slightly more fragile tortoise and it has been noted that they can catch something from another animal rather quickly.

Testudo hermanni boettgeri is by nature, usually a much larger animal. Some adult females are very large. This may intimidate a group of Thh and cause mainly females to hide and not venture out to feed, thus leading to disease.

Females of both Thh and Thb have been known to fight especially while they are gravid. Here is another video of some of my Thh showing a very angry female beating up on her cage mates.
http://www.youtube.com/watch?v=FItJ44ijcuU&feature=user

and

http://www.youtube.com/watch?v=gMEljtHSwYY&feature=user

Keepers are also newly able to differentiate Testudo hermanni boettgeri from Testudo hermanni hercegovinensis. Many do not even know that they may have hercegovinensis. This makes it possible that if you are already mixing Thh with Thb, you may even have a third subspecies mixed in with the possibility of you having a hercegovinensis.

what temps for basking, ambient temp, and nighttime temps???

Night time temps can drop low into the 60's sometimes lower. Indoors I let them drop to whatever the room is at night. Basking temp I keep in the high 90's and ambient temp 75-80.

How high can the basking spot be for Hermann hatchlings? Thanks!

hi...

I hope nobody will get mad but ppl Yugoslavia doesn't exist for last 15 years!!! I know cause my country was a part of it... so when you talk about where T. hermani hermani lives you should be more precise... like Croatia, Bosnia and Hercegovina....