Thank you for getting back to me. The behavior you're seeing isn't normal - it means something is wrong. A bird won't show any signs that she's growing an egg. She'll just lay one, and that will be the first you know about it. Your finch may have an egg inside her that she can't lay. Signs that she may be egg bound include sitting with legs apart, straining, droppings stuck to the back end, appetite loss, and lethargy. Being puffed up tells us your finch isn't feeling well.
If you think she's egg bound, this is an emergency. A bird can die in just a few hours from this condition. Here is a link to a list of avian vets by state. You may have to drive a bit to get to one.
If you absolutely can't get to a vet right away, there are a few things you can try, but success is iffy. If the egg is just inside the vent, you can put a little cooking oil or mineral oil in the vent. This won't do any good if the egg is further up. Do not try to break the egg or pull it out - this can do even more harm.
Give her some water with a little sugar or Karo syrup in it to keep her energy up.
You can run a hot shower in your bathroom until the room is warm and humid (85 to 90 degrees). Gently (so as not to accidentally break the egg) put her in a small box or cage and take her to the warm room. Watch her closely to make sure she doesn't overheat.Sometimes the warmth and humidity may help her pass the egg. Here is a site with detailed information on egg binding (it applies to all species, not just cockatiels):
Remember that these home remedies seldom work. They are just a last attempt to help if you absolutely cannot get to a vet.
If your finch isn't showing signs of egg binding, there is something else wrong. By the time a bird starts showing symptoms, it is often very ill. so, no matter what is wrong, your best choice would be to see a vet.
If you want more information on normal finch reproduction, this site will help:
If you have more questions, just let me know by clicking on REPLY. I hope your finch will be fine.