Join Date: May 2008
Location: St. Albert, AB, Canada
Marmoset, I don't think she's got the momma - just the kits,
OP - I'd suggest keeping the kittens. There's a good chance you'd never see the kittens again and that mum would either abandon or move them. She's already caught them, so I'd try and see if a local rescue can take them to foster until they're old enough to be adopted.
It's not ideal, but when you're dealing with true ferals (won't allow any contact, will aggressively protect kittens, or move them) sometimes it's about the best you can do rather than the gold standard. On the bright side, the kittens have had plenty of momma's milk until now, so they'll have the immune system boost it gives.