The calf will be about 150 pounds and 6 feet tall at birth and up and walking in about an hour.
The zoo also said April appears "a little more on edge" and is "not being as lovely as usual".
Animal Adventure Park posted a new photo of April Saturday along with a message, saying in part: "Pregnancy belly has never looked so good!"
The world has been waiting with bated breath for more than a week for April the giraffe to give birth.
The zoo didn't have a reason why 15-year-old April's behavior changed, but said it could be because, "continued increase in belly movements".
"The timeline is obviously wrong a little bit wrong", conceded Jordan Patch, the park's owner, in a Facebook Live video earlier this week.
The only difference? The much-longed-for newborn is a giraffe - and one which is not afraid to take its time making an entrance. Once the calf is born, it will remain in the barn with April until naturally weened from his or her mother. The zoo plans to have a contest to name the calf once it is born. Almost 95,000 people were tuned in to watch the YouTube stream around midday Friday.
If you've been to the Denver Zoo, you've probably seen Kipele. The excitement reached a fever pitch last week when the live feed of her pen was briefly yanked off YouTube after animal rights activists complained that the video contained "nudity and sexual content".
Cheyenne Mountain Zoo in Colorado Springs has been collecting blood samples from its giraffes and recently started banking plasma for emergency situations.
"I'm malnourished and dehydrated ... my dog is turning fat because I just can't stop watching and he's being neglected", the Facebook user posted.
HollywoodLifers, what did you think of Tom's narration of April's webcam?