You are on a mission to find out how to keep your Lesser Sulphur Crested Cockatoos from screaming and biting for sure. This is good of you.
You are on a mission! With the goal of finding out how to keep your baby cockatoos from sceaming and biting. Good for you!
You are wanting to DIG and read, good for you!
I appreciate your effort and I'll try to give you a very simple, basic, plain 'pep talk'.
Some people come here and want to be spoon fed but not you as you want to learn to use the search engine. This is great and how it should be. You have to DIG and read and read and read. Good for you. You gotta get busy here and you will soon master the search engine. You landed on the right perch here.
Your cockatoos are still very young and now is the time to build trust between you and them and to interact with them daily. A regular routine for feeding, handling and sleeping is good for them as it builds trust between you and your cockatoos. They know what to expect and when to expect it. They know you as steady and loving and kind. They need to have this trust in you and your loving care of them to trust you later in life when they grow up more and start to scream - vocalize - and get hormonal and nip and bite at you due to growing up.
If you build trust with them now while they are babies they will be easier to work with and train later when they become teenagers! What you do now in building trust and having a good routine and schedule proves to them you are dependable and worthy of trust and this is good. It makes the terrible teens much easier with a cockatoo that has trust in you.
Building trust and being a good and dependable and predictable human to your cockatoos is the goal right now. A regular schedule or routine is good for you both right now so work on this. They need love and patience and I know you'll give them tons of both.
Cockatoos are hard to learn but you can learn about cockatoos. You are learning alot right now just by reading this post and the post of all the members here. What Elliott posted is excellent as is usual for Elliott and the long time members here and I learn from them all the time.
They need a routine - a regular bed time and a regular wake up time. This helps them and you both. They need at least 10 hours of sleep each night maybe even 12. They are young and may want a nap during the day also. A nap is good for them in the afternoon as young cockatoos.
Cockatoos wake up with the sun up and go to sleep in the evening at sun down. They have a need to vocalize, scream, when they wake up as to say Good Morning, I'm here, it's me! I'm alive! and I want you around me! and a need to vocalize, scream when they are getting ready to go to bed sun down to say Goodnight! Sleep Well! You're Ok and I'm Ok. This is natural. Because they are young they are not yet fully adult and are still quiet babies right now.
If you give them plenty of nice toys they are happy and it keeps them busy. Cockatoos like to be kept busy with lots of toys in the cage. Bird safe toys are good to buy and you must have some in the cage so they don't get bored. They like all kinds of toys online for cockatoos and large parrots. They need safe toys as much as they need food, water and your love.
The food should be what they were eating when you got them. If you got them eating pellets buy the same pellets. If you got them eating seed mix buy the same seed mix. You can give them green beans, peas, mixed vegetables, apple, pieces of toast, cooked soft brown rice, cooked oatmeal and more. Just don't feed them avacodo, candy, meat, chocolate or junk food. Nuts from the pet store for parrots are fine and make nice treats. Nutriberries and Avicakes are nice foods also and are a fun treat. There is much here about diet to read.
They are still young and the best thing to do is to just love them right now. Build trust in them. Show them you care for them by caring for them. They need to see you as steady, on time and good. A regular time in the morning for feeding them breakfast is good and a regular time in the evening to feed them supper is good. Keep pellets and seed mix for them in the cage all the time but give them fresh pellets and seed mix each day for breakfast along with other foods like above at breakfast and evening supper.
Handle them and say to them 'step up' when they perch on your hand or arm. Tell them 'good bird' when they do. Always say to them 'step up' when they perch on your hand and arm. This builds a trust bond for both of you. Don't start bad habits now with allowing them to perch on your shoulder. They may all on their own go to your shoulder. This gives them dominance over you due to the height and this is cute when they are babies and young but it's not safe with a teenage and adult hormonal cockatoo as they can and have and do bite lips, ears, back of neck, eyes.
A video of a serious bite that came close to eye when a man made a mistake handling a hormonal adult cockatoo. Cockatoo Bite on Face Above Eye
Build trust by letting them see you do all the things you do each day in your home. Cleaning the floors, bringing in food and placing in the kitchen shelves, exercising, just walking around your home. Let them see you when in their cage doing all that you do in your home.
When they are out of the cage make sure you watch them so they don't break anything or eat anything like furniture or books or magazines. They don't know that the remote control buttons are not food! They are babies right now. So watch them good if you let them out of cage to walk around.
Just post any questions you have and we will answer as best we can.
Try to find the time to read the article I posted above, Living With a Cockatoo
It's a long read but give it your best shot!