Just drain the can of sauerkraut into a colander and give it a rinse, that will take a lot of the salt out if you are worried about it.
It would be good if the sauerkraut works. While yes, a bird may be able to live with a screw, staples, pieces of metal stuck in the gizzard, body, etc. Sounds well and good but over time the break down of the metal can and often does lead to heavy metal toxicity.
With poultry, this is called "Hardware Disease"
https://tvmdl.tamu.edu/2019/10/14/hardware-disease-in-backyard-chickens/
It would be good if the sauerkraut works. While yes, a bird may be able to live with a screw, staples, pieces of metal stuck in the gizzard, body, etc. Sounds well and good but over time the break down of the metal can and often does lead to heavy metal toxicity.
With poultry, this is called "Hardware Disease"
https://tvmdl.tamu.edu/2019/10/14/hardware-disease-in-backyard-chickens/