The cost of caring for a service-animal would be considered a medical expense and deductible on Form1040, Schedule A, Line 1. Costs of care would include food and veterinary care. You would need to provide a doctor's note of what specific medial need the animal provides (ie guide dog).
The cost of fostering a pet for a qualified 501(c)(3) adoption organization would be deductible on Form 1040, Schedule A, Line 11. Costs include food, veterinary care, supplies, and transportation.
Performing pets may qualify for deductions if they generates taxable income such as movies, influencers, or cash prizes in competitions and events (ie Great American Dog Show). Make sure to keep adequate records of the income and expenses.
Our recent blog goes into more detail: https://blog.turbotax.intuit.com/tax-tips/can-i-claim-my-pet-as-a-dependent-53/
