Article 

Oxalic Acid Content of Selected Foods

High dietary levels of oxalic acid or oxalates may promote urolith or bladder stone formation in herbivores like the guinea pig and tortoise. The following chart shows the oxalate content in 100 grams of selected raw foods.

Article 

Urolithiasis in Ferrets, Rabbits and Rodents

Urolithiasis is characterized by single or multiple calculi throughout the urinary tract or by the presence of sandy material within the bladder and urethra. Uroliths are fortunately more of a historical disease in the ferret, while calculi are still an important problem in rabbits and rodents.