I no longer have my companion flock but I can tell you a bit about the birds I have kept
I find that my budgies (who I do still have a flock of) eat little and often and when they do they're very frantic about it! The babies that I keep back tend to be a lot more adventurous with their foods and will eat fresh food very happily, but only after they've bathed on it! If I hang millet from their toys in the aviary then it gets all of them quite active but I've noticed that the older birds will sit on near by perches and nibble at the stuff while the younger birds will literally be hanging on to it upside down and eating as fast as they can
My aviary cockatiels are very reserved eaters and eat maybe 3-4 times a day. They will sit and eat slowly and not bother all too much. With fresh food they'll maybe have a quick nibble but will soon be satisfied and go to sleep
My red fronted kakariki who is getting on a bit now, Ralph, has almost grown out of the chicken scratching of the food bowl. Kakarikis have this very annoying habit of scratting at their food. They will sit in their bowl and kick it everywhere. Heaven alone knows why as the bowl consists of the same foods throughout! With fresh food he will take them and hold them in his foot while he enjoys them but will often drop them, fly down to get them and go back up to his perch again
My yellow fronted kakariki is only a few months old and is a big scratcher. He likes to make sure that the food is half way across the aviary before he can eat it. I think he likes to empty it all on to the floor so he can forage on his own! He likes to eat fast and also likes to hold fresh foods in his feet
My black cheeked lovebirds will sit and eat bottoms up for anything up to 10 minutes! Once that head goes in to the bowl they won't come back up for air for a long time
If they're eating a bowl of fresh food, they'll usually come up and turn around to look at me and they'll have a great big smush of food on their faces!
I recently got a pair of black masked lovebirds and I notice they do the same thing. Maybe it's an eye ring lovie thing
I used to keep peach faced lovebirds and all of them have been food demons. I used to put a heaping pile of chop in with them on a plate and they'd have it cleared shortly after! All of them would gang up on it and demolish it, getting very foody beaks in the process
My companion cockatiel, Harvey (who is no longer with us) would eat very, very fast. I have no idea why. I had never had a hand raised cockatiel but as I bred and raised him myself I found him VERY hard to wean. When he did wean he would scoff his food as fast as possible. I'd have to fill his bowl a couple of times a day so he could eat little and often as I felt that it was quite worrying! He was about a year old when he passed away, so you could say he was still a baby
I had a young green cheek conure, Dexter, and she was quite a slow eater. It was like she would deliberately get food all over her face and chew everything veeeryyyyyyyy slow. She was the first hand raised bird I had bought. Now I've also had another 2 green cheeks, a green cheek hybrid and a black capped conure. Come to think of it, they were all different ages and species but they all ate the same!
Indian ringnecks and Alexandrine parakeets are also quite slow, regardless of age. I noticed it with my guys anyway!
Lories and lorikeets, well, they're unique so I won't go in to those
My orange winged Amazon, Clyde, would eat fresh foods as fast as possible but he would eat his dry foods very slow. I don't know why. I don't think he had ever been fed much fruit and veggies (and anything else good!) before he came to me so perhaps he was just really enjoying them? I don't know. He was around 4-5 years old when he passed away
I had a rescue lesser sulphur crested cockatoo and honestly, he was probably one of the most messy birds I had ever encountered. I have heard from numerous people that it is just a cockatoo thing, but they have shovel beaks. He could have a bowl of pellets and he'd still shovel almost all of it out... Kind of like how the kakarikis scratch? But with his beak
Literally just flung everything out of the way to get to the good stuff! Like I said, it could of been a bowl of chop and it would end up all over the walls still, even though the bowl would be the same throughout! He was 18 years old
The lineolated parakeets I had kept had been very slow bottoms up feeders like the black masked and black cheeked lovebirds. They were an older breeding pair
The four aviary parrotlets I have kept were very fast, little and often eaters... a bit like the budgies I guess?
Hope that gives you a rough idea anyway, it's quite hard to describe them all when I'm trying to get ready for work haha!