Hi Laura,
Has she been wormed?
Does the blood come from her anus or vagina?
Thanks,
Terri
Dear Laura,
Blood in a young kittens stool is almost always related to a parasite.It can be a GI upset from the food change too.
Worms,coccidia, giardia:
cociddia http://www.marvistavet.com/html/coccidia.html
Giardia http://marvistavet.com/html/giardia.html
It could also be from ingesting a sharp non food item but that is less likely since she is eating and happy.
The best thing to do is take a stool sample to your vet.
I hope it is nothing and your baby will be fine. Please let me know how she is,
Sincerest best wishes,
Animal Healthcare expert
Expert in pet health and behavior. 20 year experience with animals.