Your lovebird is probably reacting to the changes going on with the move. Since I do not know what area of hte world you live in, if you are in an area where the weather is cold and your home may be pretty cool, you should probably have her checked by an avian vet.
There are two likely reasons for her bald spot. One is that she is going through a molt and is simply losing a lot of feathers there, enough to make it look bald. But if it is clearly a bald spot with no feathers in it at all, she is either plucking the feathers or rubbing them away on something.
Sometimes if a bird is having raging hormones, they may rub against something in an act of simulated mating. This could potentially result in a bald spot.
If she is plucking, it is almost certainly a result of the recent stress. But, stress can also bring on illness and since parrots do hide any sickness until they are so ill they can not hide it any longer, a trip to the vet would be a great place to start.
Once you have her health assessed, if the vet finds nothing amiss, you should allow her a bit of time to adjust to the new home, but also you need to give her lots of toys to entertain herself when she is in her cage, especially if she is a lone bird. But even if she has a cage mate, they still need lots of toys. Toys that allow them to simulate preening are good choices for parrots that tend to want to pluck. Chewing toys are good too because they keep the beak busy doing something besides plucking.
Also, be sure she is getting a complete and balanced diet made up of 30% bird seed mix for cockatiels / small parrots but which does not have sunflower seeds in it or very few sunflowers. The rest of her diet should consist of fresh fruits and vegetables and other humans foods. You can find a very good, informative article about what to feed and what to never feed your lovebird by clicking here.
There is one other situation in which a female parrot will sometimes pluck a small area right on their breast and no where else on their body. When a hen lays an egg and is sitting on it, if she feels the temperature is not just right by simply sitting, she will pluck what is called a "brooding patch" so that her body heat is closer to the eggs, helping her to keep them at the proper heat level. But since you didn't mention a nest, I am reasonably sure this is not the cause and that the cause is the changes in her life due to the move.
I would also like to mention that since you have moved to a new home,. Often when a person moves into a new residence, they do a lot of painting, replacing carpeting or floor treatments or furniture. If you plan to do these things, be sure to consider the fact that paint odor can kill a parrots and any product that has been treated with a strain-resistant finish can be deadly. If you have the carpet cleaned, do not allow the cleaners to put a "scotch guard" or other stain proofing product on the carpet. It can kill your lovebird because it is teflon based.
I do hope this helps. If you need more information, please use reply to contact me.
Breeder
over 25 years breeding, taming, training parrots.