Are you all set to start tubing? If so, I think you're probably a little nervous about this. So I would begin with a little of the warmed ringers. A fourth of a cup of fluid is about right for most chickens. This will get you both comfortable with the procedure.
After that, both of you rest for half an hour. Then check her crop to see how full it is. My rule of thumb is that most crops on standard size chickens will hold half a cup. So you may safely tube a fourth of a cup of baby bird mix into the crop for this second session. I wait a couple hours and do another feeding if the crop has emptied. Always check the fullness of the crop before tubing anything into a chicken.
The chicken may react to the crop filling by suddenly squirming. Pause until she settles down, but check to be sure her crop isn't already full. Usually, this procedure is well tolerated, and the chicken has a feeling of contentment as you fill the crop. Just be sure not to overfill.
After that, both of you rest for half an hour. Then check her crop to see how full it is. My rule of thumb is that most crops on standard size chickens will hold half a cup. So you may safely tube a fourth of a cup of baby bird mix into the crop for this second session. I wait a couple hours and do another feeding if the crop has emptied. Always check the fullness of the crop before tubing anything into a chicken.
The chicken may react to the crop filling by suddenly squirming. Pause until she settles down, but check to be sure her crop isn't already full. Usually, this procedure is well tolerated, and the chicken has a feeling of contentment as you fill the crop. Just be sure not to overfill.