how much food

I have a crossbeak/scissor beak EE and she's been eating mash for a while. She has stopped gaining weight and is less than 1/4 the size of her siblings. I've began tube feeding her 20ml twice a day. Is this enough? She isn't able to eat anything so the only food she gets is from tube feeding...

I have 10 adult hens and I am buying 50 lbs of food about every week and a half. The birds have plenty of free space to run. I have 2 feeders that hold 25lbs each. I am having to refill them about every 8-10 days. Could something else be eating the chicken food at night? Or are they just...