You may find these 2 articles helpful. One is syringing fluids and/or medications. The other is how to tube/crop feed.
https://www.backyardchickens.com/ar...dications-to-all-poultry-and-waterfowl.73335/
https://www.backyardchickens.com/articles/crop-feeding.75454/
https://www.backyardchickens.com/ar...dications-to-all-poultry-and-waterfowl.73335/
https://www.backyardchickens.com/articles/crop-feeding.75454/