By peoplestaff225
Updated August 24, 2009 06:00 PM

Chyler Leigh‘s family has been in the midst of a steady growth spurt for the past six years. But with the May 7th birth of their third child, Anniston Kae, the Grey’s Anatomy star and her husband, actor Nathan West, have found that parenting gets a little bit easier with each addition to their clan.

“Going from zero to one is a huge shock,” Chyler, 27, tells PEOPLE. “One to two was a little more challenging. Two to three was a bit more challenging, but once you get used to multiples you figure out how to put things together quicker. You learn how to organize. With number three coming, you get more confident as a mom. The third time around, you know what to expect. It’s like calm mom, calm baby.”

It doesn’t hurt that Anni, as they call her, is a mellow baby. “She started sleeping through the night at two months,” Chyler says of the infant, who was born just 10 days after Grey’s Anatomy‘s fifth season wrapped. “She’s such a happy baby. This one is just all smiles, and she talks a lot,” the actress notes. “She’s pretty much perfect.”

The well-behaved baby has already won over the actors on her mom’s hit show. “Justin [Chambers] nicknamed her Baby Elvis because of her mohawk,” Chyler says. The cast has showered the new arrival with gifts — mostly of the eco-friendly variety: “Justin got us organic cotton onesies, as well as gifts for the older kids,” she shares. “Eric [Dane] got us organic baby diaper ointment and lotions and Shonda [Rhimes] got us a huge Saks Fifth Avenue basket, which was really sweet.”

Click below for Chyler’s thoughts on the “tricky part” of going back to work, as well as a second photo!

Anni, who is going to set with her mom and a caregiver most days is “so easy going. She’s so happy to be held, but good at having her own independent time. That’s made a big difference,” she says. “I think she kinda knew she was coming into a hectic household!”

For Chyler, the “tricky part” of going back to work with a 3-month-old has been balancing the demands of a nursing baby with the Grey‘s schedule. “If I’m filming and have breastmilk, I’ll give her that, race back and have [Anni’s caregiver] supplement with formula,” she explains. “Sometimes she might get full formula. We’re taking it as it comes.”

Although Chyler initially thought Anni was “getting a lot of formula,” she admits that her schedule makes it difficult to pump. “There’s a guilt factor going on there — you want to give your kids the absolute best,” she explains. “Often moms are way harder on themselves, so there’s a lot of adjustment [there]. But it’s like, you know what, she’s obviously healthy. She’s loved beyond measure, and she’s a happy kid.”

And also the center of attention! Older siblings Noah Wilde, 5 ½ and Taelyn Leigh, 2 ½, have made the adjustment well, Chyler says. “Noah’s been great. He’s good at occupying himself. Taelyn, we had a short two weeks about a month after she was born where she got aggressive — it was an attention thing. We try our very best to make sure she gets one on one time with one of us or both of us. Noah is protective. If Taelyn wants to play with the baby, he says, ‘Be gentle.'”

Helping with the transition were a few new toys! “We went and bought a gift — a little green frog — for Anni [from Noah and Taelyn]. And we got gifts for the kids from Anni — Woody and Buzz dolls for Noah and a rocket from Little Einsteins for Taelyn. Anni knew exactly what to get!,” Chyler laughs.

For Chyler and Nathan, the addition of a third child — “a big surprise,” the actress admits — meant it was time to upgrade! “The car, the house. Everything gets bigger,” Chyler says. “We had to get a double stroller, we carry a lot more stuff and we have a lot more laundry.”

Chyler and her husband say that they don’t plan on making another addition to their family any time soon. “Three kids is a lot,” adds Nathan, 30. “But I couldn’t imagine our family without her. She just completed it.”

Source: PEOPLE, August 31 issue

— Lisa Ingrassia