I think a broody is apples and oranges. One, not sick and trying to heal. Two, They do get off the nest to gorge till lock down. They loose a ton of weight, get mites a d molt after. So. Meh.You could let some fruit ferment....Is the 30 ml food, or water? A broody can go weeks without eating, right? More watery poo this morning, with some solids. She ate a little oatmeal liquid, and had her electrolytes. Trying about every 2 hours for hydration. Does that sound ok?
The 30 mils was shared with me and I have had great success using it as a guideline. If my chook is slightly off food I syringe feed 30mils. I mix a protein powder, vits, electrolytes and meds into a shake like consistent slurry a d suck up 10 mils into a syringe with a 1/8 × 2.5" tube fastened to the tip- I also burn the tip to get rid of any sharp edges. This I insert down the throat.
You'd have to be careful with your gal as she may have sustained an unknown injury... but I gently lift beak up giving me a clear shot to get 10mils down their throat.
It has helped me help my chooks overcome some pretty fatal stuff ♡