3 week old orphaned kitten difficulty latching/eating advice?

[yawaaaa]

Rescued a lone kitten two days ago. He should be about three weeks old, his ears are open and his teeth are just starting to come in. He's really small for his age (he's smaller than my hand), but seems pretty healthy; he's not lethargic, weak or anything like that. He's actually pretty active already and walks/wobbles around a lot. My issue is that he's having trouble taking to a bottle. He ate with minimal issue on the first day, as in it's obvious he's not used to the bottle but he was able to get in a pretty good amount each feeding. But on the second day, he would latch for maybe one or two seconds and let go. Sometimes he won't latch at all and just start chewing on the nipple or backing away. I've tried making the nipple's hole smaller and making it bigger in case maybe he has trouble with how much formula is coming out. I've tried putting him in a towel burrito, stroking his back and forehead while trying to feed etc. Sometimes I get lucky and he latches the entire time where he gets around 5 to 10ml of formula, but most of the time it's what I mentioned. I try to feed him every three hours, but most of the time he doesn't latch so he's not getting that much. I'm using Beaphar kitten formula, he has a heating pad he can use, he pees and poops just fine too.

I was wondering if maybe he won't latch because he's just not hungry yet? Or maybe he is and he's just not used to the bottle? He usually walks around and nuzzles my hand whenever he refuses to latch which makes me think that he's trying to look for a nipple, sometimes he'd just roll on his back and purr. I've hand-raised orphaned kittens before even younger then he is but he's my first one that just won't latch properly, I was wondering if anyone has any thoughts or advice? Thank you in advanced! Pic of kitten attached below

 

[Sarthur2]

He may not be hungry yet since he’s shown he can latch. Offer, but if he doesn’t suckle, try again in another hour. Also, try a small syringe. The nipple of the bottle may be a bit large for him right now.

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