My bichon is bleeding when trying to have a bowel movement.
Bleeding from the anus or having blood in the stool may occur due to various causes like parasites, food, hemorrhagic gastroenteritis, rectal wounds, parvovirus and even stress.
On the other hand, In senior dogs like Kayla it possible some of her systems are affected with failure / damage, like digestive system.
If occurred with vomit and diarrhea, it is very important to visit a vet as dehydration can become very serious very quickly.
As treatment can vary greatly depending on the cause, you should visit a vet clinic as soon as possible, for consultation and diagnostic testing.
All the best.