Hi, welcome to AA and thanks for joining to seek help for your baby. We could use a little more information from you. If this young baby was kept by the breeder along with other siblings there's a good chance it's frightened and stressed being in a new home alone without another bird to cuddle with .... emotional support if you will. Sometimes a baby will refuse to eat with a new person in the beginning when there is a drastic change in it's environment. At this age it's imperative this young bird receive the nourishment it needs and on a schedule just as the breeder had. Same formula, same consistency, same temperature. It can help if you lower the lighting if you are trying to feed it in bright light. You do have to see what you are doing to prevent accidental aspiration. What are you keeping the baby in? Something similar to what the breeder kept it in? You might consider taking a small towel and rolling it up and placing it in the container for it to sit next to but be very aware it could chew on the towel so be very observant about that. Someone else may have another better suggestion regarding the towel. Most importantly you do not want it to ingest any foreign objects. Bedding can be layers of paper towels that you remove as they get soiled to keep it sanitary. Did this breeder show you his method of feeding and let you feed the baby in his presence or even show you how they mixed the formula? You can't expect your hahn's to behave as your cockatiel did... they are two very different species of birds. If it still isn't taking any formula the best you can do for this baby is to make an appointment as soon as you can with an avian vet. At this point in it's development you need a base line on it's weight and overall checkup to make sure there aren't any hidden illnesses. Baby's can go downhill quickly so please don't wait. There was another person a while back that bought an unweaned macaw , I'm not sure of the species of macaw now, but he had problems with his baby and fought quite hard to save it and in the end lost it. It was one of the saddest threads I've read. Breeders truly need to be more responsible with following through with the birds they raise and only selling them completely weaned and eating solids well before letting them go. Hand feeding does not ensure the bird will bond more to you and can be the complete opposite so don't be surprised if at weaning you experience a maturing baby that wants nothing to do with you. It happens all the time no matter what the species of bird is. We see this quite frequently on AA where people don't understand why the sweet baby grew into a biting bird. If not as a youngster then later when they sexually mature they can also go through a drastic change. Breeders and sellers are simply neglectful to inform buyers of all this additional information. We wish you well, hope you stay on and keep us informed ( and hopefully) with positive updates.