Baby Zebra Finch

Question
I have had Zebra Finches for several years and have had several clutches. Recently I had a female die after the clutch hatched. I have been hand feeding them for the last 2 weeks. This is my first time hand feeding. My question is?  A couple of time while feeding they have stopped begging and become silent. The Crops are not full. The one acts like he cannot make any sounds at all. I have been very carefull with all of the foods I give them, and keeping everything clean.

Answer
Babies will sometimes do that. The best I can figure is that they're full enough to be tired. I usually try stroking their beaks with the syringe to get them to open up again. All else fails, you just come back later to finish feeding. I wouldn't be too worried about this until they start to lose their pinkish color and start to turn yellow