we don't exactly feed to sleep (used to when she was a newborn) but she does sometimes fall asleep during her bottle, often she'll close her eyes and drink but open them once I put her on my shoulder to burp her (if I wasnt so unco and could move her without disturbing her too much she probably wouldn't wake up!). If she is really tired though she will fall dead asleep during the bottle, she may only drink half or 3/4 of it and fall asleep...once her mouth falls open and she's not sucking on the teat so the bottle comes out easily then i know she is asleep! So yep it is possible, although it may take a little while for her to get used to it if she is used to being b/f.