The Tylan200 dosage for large-fowl is .5ccs injected into one side of the breast once daily for 3-4 days. Alternate the side of the breast that you inject into, and use a small guage needle, as Tylan can make the injection area sore. Improvement should be seen after 2-3 days of treatment. Do not give probiotics, dairy products, or apple cider vinegar during Tylan treatment. The VetRX should help somewhat, as well.
I have never tube fed before, but have found other ways of getting sick birds to eat. Here are a few:
1. Mix some feed and perhaps some applesauce with water (preferably with vitamins/electrolytes in it) to form a thin soup. Hold a spoon with this mixture against the tip of the bird's beak; with many birds this will make them kind of start drinking the liquid. You can also suck up some of this "soup" with an eyedropper and drip some of it on the side of the bird's beak to get it to swallow.
2. Moisten some feed with water to form a sticky, but not too watery mixture. Form this mixture into bite sized morsels. With the help of someone else, gently open the bird's beak. Pop in a piece of the mixture, and then close the beak. This will usually cause the bird to swallow, if not, get some water and drip it into the beak to encourage swallowing.
3. Although this isn't as great an idea as the two above, you can also squirt some water into the bird's throat, or just put the water in the lower part of the beak. The only disadvantage of this is that it is possible to get the liquid into the bird's lungs.
In case you do manage to find a tube and want to tube feed, these are a few links to threads that might be helpful:
https://www.backyardchickens.com/t/722041/how-to-t-feed-a-sick-chicken-and-give-subcutaneous-fluid
https://www.backyardchickens.com/t/...h-my-bird-pics-for-visuals-very-detailed-post