Don't touch newborns or their mom will eat them
Fact: in almost nine years of breeding LOTS of different rabbits from various genetic backgrounds and handling styles I have yet to run into a doe who will eat her kits after I handle them. Not even once. I've had does that will eat their kits after the kits die (that's just being a clean up crew)...but I"ve not had one that will deliberately start eating their kits while they are alive.
Fact: I have met does that don't much like their kits after they are out of the nestbox and one who would MAIM her offspring so she went to the sales barn with the kits weaned early and sold to pet homes only when well old enough. But that's not a handling of babies issue.. that's a genetic flaw in the brain of the doe issue.
Check on the kits first thing in the morning
And it's actually good to check them twice a day. You want to make sure all the kits are alive and none are dead. For large litters this means taking all the kits out and physically counting them. Checking that none are being missed by mom or have run into any sort of problem or are even dead. Dead kits.. in the winter they freeze and chill the other kits, in the summer they rot and attract flies. Neither is a particularly good scene for surviving kits.
Fostering Kits is difficult
What you DON'T need to do is put vanilla on their noses. You really don't need to.
For difficult does you merely remove the nestbox. Plunk the kits in you want to foster and an hour later put them back in with momma, watch her reaction and leave 'em be. MOST does will simply go oh.. they are back.. check on them and go about their daily routine. The odd doe will note the strangers and separate the kits out. Most does aren't that discerning.. they just feed the kits when there is need and cause no fuss.
General rule of thumb. foster according to size. Foster smalls with small and bigs with bigs. OR ONE big with several smalls. DO NOT put a small with several bigs as it will get knocked around too much.
Remove larger kits before you remove smaller kits.
I've had some litters when one doe was an excellent milker and I just fostered small kits from various litters to her for a good month. I just kept mixing and matching sizes and kept her feeding the wee ones that needed more help.
Raising buns is fun... but has a learning curve...mostly with the handler learning what their rabbits are like and adjusting to their needs as they help their rabbits adjust to them. :)