Great info.Yep! I've been tube feeding ever since my vet had me do it for an injured drake a couple years ago. He recommended it for him to help him after a predator attack. When done right there is no risk of aspiration as long as you don't overfill the crop. I've got a little house chicken now that wouldn't be alive had I not tube fed her when she was sick, and a peacock too.
I've also saved the life of a newly hatched chick that arrived in an order from a hatchery that wasn't doing well and wouldn't eat or drink. I tube fed it a little water and nutri drench and within an hour it was up and eating and drinking and has done very well.
There are lots of people who keep cross-beak chickens like this little duckling and they tube feed them daily. There's actually an article about that here.