MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
Pleased you like my Ratz... it is a fun design.
The bottom line is PLA is very brittle so easy to break in areas that are thin. Treat them with respect so don't use any excessive force and they are fine...
Having said that, using more shells and greater infill will help for sure. Many slicers apply 2 shells / 10% infill by default. Using 50% infill will greatly increase the strength. However, it won't increase the print time and filament used by a significant amount because the model is hollow.
Filament brand and condition can also make a big difference...
I hope this helps.