thank you. Oh, I don't feed them often, the best I am doing right now is twice a day. I weigh them before feeding and right after. The regular increase is 1g only. Sometimes 2g, and only once someone increased by 3g

If they're gaining weight they're getting enough to eat. It's still a good idea to offer some formula in case the parents stop doing their job, but it sounds like the chicks are OK.

They are not gaining weight. Probably just not losing it. I mean, I weight them after feeding to see what they ate (if the chick is 1g more than before feeding, then he ate 1g of formula, right?)

I need a bigger something to give them formula. I am using 5 ml medication pipette (plastic), and often I have to interrupt feeding to go get a new portion when they just started to eat well. Also, it really helps to make a fresh formula, instead of making one big cup for all of them (it doesn't do too well thru our very long process).

recommendations to feed about 10% of the weight - is it per feeding, or per day?

It's per feeding.

If their weight is holding steady and they're healthy and active, it's OK. They're fledglings and aren't actually expected to gain weight right now. If they lost weight due to lack of food earlier then they need to gain that back, but once they reach a good weight they shouldn't gain any more.

thanks.
What should be night hours for them? We turn the light off at 10pm (which I think is late) and get them up soon after 7am. Normally I let my tiels sleep longer than this but I thought they shouldn't spend too many hours without food - ?

its 10.13 and I still have lights on because everybody eating in the cage
today I made formula but all 4 were so concentrated eating something else, that I decided to pull them out later.

I finally opened unhatched eggs that were left from the first clutch. 2 of them were just like chicken eggs we eat - with liquid yolk and white. The third one had also yolk with orange tint but it was all dry inside. Was this one fertile but died early?

All 3 eggs looked fine from outside - not black or rotten or anything.

The babies are old enough to get through the night without eating, so it's OK to follow a normal nighttime schedule with them.

It sounds like at least two of the eggs weren't fertile. If the third one was fertile it must have died at a very early stage. But it's likely that it was actually infertile, and just dried out faster than the others. There might have been a tiny crack in the shell that made it dry out faster.

Lots of shaking in the cage when they flap their wings and chasing the father. Worried for the new clutch well-being.

6 eggs this time. Now mom is out of the cage much more so the daddy is incubating more time during the day. Interesting, but the chicks don't associate mom with feeding, dad only. I wonder what its going to be like when (if) any new babies are born. I mean all the older chicks and the babies.

Sorry for the slow reply, I'm out of town for Thanksgiving. The older babies will probably wean sometime soon so the parents will be able to focus all their attention on the new clutch. It's possible that the older babies might help a little bit with feeding the new chicks.