Dd is 15 weeks and we're moving onto formula. She's on Pepti 1, we started off by mixing it with breast milk and now its formula only. Only doing one feed a day on formula at the moment. However, we're struggling. She tends to chug 3 ounces straight away, then stops and refuses to have the teat in her mouth. I know she's still hungry as she's chewing on her fist and will accept breast if offered (I don't offer it though - I'm more stubborn than she is). I've tried nuk, dr brown and tommee tippee bottles - all the same. Help! Any ideas?