So it would not be too far fetched to assume that she is an old/very old hybrid which sadly are prone to issues of the reproductive system and all kinds of tumors.
Although like @azygous mentioned, there might be a possibility that the bleeding was caused by an aggressive strain of coccidia, I...
This does not look good at all.
I am afraid that the cause for her crop issue might be some kind of tumor obstructing her digestive tract farther down. It looks as if there might have occured a rupture of the tumor.
What colour does her skin have?
How old is she and what breed?