Homeopathic medicines largely operate through their energy signature patterns which the body recognizes through its electrical and nervous system. The size of the animal will not make any difference to the amount of homeopathic drops or pills required as one dose.

Herbal medicines contain the food and nutritive values of the herb, and work through the digestive and alimentary system. When these are  combined according to Diana Moon-Hayes method one gains the best of both systems enabling a more rapid healing response even in situations where no response has been noted previously. 
However, when giving herbal medicine (brown liquid) it is important the amount given each time mixed in with the food and offered

Safe and easy application to all species and age.    

For wildlife as pets or zoo type of habitat, application of the homeopathic formulas can be administered in their water dish, trough, or bowl.  Repeating once a week.  As homeopathics are energy medicine and will stimulate the vital force to heal when out of balance only the animals that need this healing will benefit, otherwise nothing will happen for the ones that drink out of the same water.