ANSWER: Congratulations on your new Quaker Parrot! Quakers are fabulous parrots to have as part of the family. We have several ourselves and really enjoy their talking ability and their fun antics.
The answer to your question can vary a bit depending on the color of the various Quaker color mutations. Most weaned normal green Quakers weigh in anywhere from 90 to 120 grams on average. Younger Quakers usually weigh at the lower end of the scale as they are still growing and forming body mass.
Often Quaker Parrots of all color mutations who have recently weaned, ages 3-4 months usually, may actually loose some weight as they loose some of the "baby" weight that they maintained from their handfeeding formula. This weight loss should not last long before the weight begins to go up again, and should not be more than a maximum of about 20% of their previous total weight at weaning. As young Quakers begin to eat new foods such as seeds, pellets, bird breads, other cooked foods, fruits & vegetables, they should begin to build themselves up in size and steadily gain the lost weight back.
Some of the color mutations such as the Blue Quakers which your bird is, in our experience can be smaller in size than the normal greens, and they will weigh less as babies and even as adults. We have seen Blue Quakers who weight about 60-80 grams when young, and not much more when they reach adulthood. Depending on their genetics, they may appear more petite always than their normal green relatives. Some do however eventually grow into an overall size that is close in size to the green Quakers so finding out info on the parents should help you know the probable average weight for your particular bird. Good breeders should keep weight charts and histories on their breeding pairs, and past clutches of babies, which would be very helpful in answering your question of weight.
If you do not have lots of experience with newly weaned parrots, we would recommend you talk with the breeder if you can of your concerns to get some additional feedback. Also, if you have not had your new baby health checked by an experienced Avian Veterinarian, that should be a top priority in order to get established with your Avian Vet, as well as ruling out any health issues early on that might cause your bird to loose more weight than normal.
A very good web site for Quaker information is Stanley's Quakerville.
