PORTLAND, Ore. -- Oregon Zoo officials in Portland say after a week of antibiotics and a blood transfusion from an adult condor, an endangered California condor chick has turned the corner and is getting stronger.

Zoo staff have worked feverishly this month to hatch the underweight and shell-bound bird. Monitoring the egg at the zoo's Jonsson Center for Wildlife Conservation, keepers determined it would not be able to hatch alone.

Fearing the chick would suffocate, they stepped in and helped -- a worst-case scenario for them. Keepers broke away part of the shell and removed the chick.

 Photos: Timelapse of condor hatching

"The hatch went well, but it was an extremely small chick, our lowest hatch-weight yet," said Condor Curator Shawn St. Michael. "It is common for chicks to be pretty quiet for the first 24 hours after hatch. It's an exhausting process. But we became concerned when this chick failed to perk up the way we would expect after his rest."

St. Michael and condor keepers provided around-the-clock care, administering antibiotics and enlisting the help of an adult condor, Nootka, for a life-saving blood donation.

"Thanks to the hard work of our staff, this chick is looking good now, and we expect it will be just fine," said St. Michael. "The chick will be puppet-reared by human foster parents and later mentored by another adult condor," he added.

The assisted hatch is the fourth successful hatch of 2008, with one more expected in early June.