Try a local slaughter house for very fresh tissues. Veterinary diagnostic
pathology lab (university or otherwise) may also provide what you want
provided the tissues are from animal euthanized and not laying around
before necropsy.   Hospitals labs are willing to help you.

As for rodent tissues, yes, they have been used, including the tiniest
tubular structures from a mouse.  Visited with a DVM pathologist who
reviewed the slides.   There are several people from the veterinary area to
read the slides with expertise in animal species tissue morphology. As long
as the tissues meet criteria for size and specific organ requirements, even
a mouse will work.  

Good luck on your exam.


 


Gayle Callis
Veterinary Molecular Biology
Montana State University
Bozeman MT 59717-3610
406 994-4705
406 994-4303