Mystery Breeding?!

Hi I'm new to this site. I got 2 female Rabbits for my children last Christmas, one lop eared and one straight. We let them out so they pretty much have free reign of the garden and go back in their hutch on there own. About 2 months ago the lop ear didn't cone back 🙁 So we now only have the one. So imagine our surprise today when I find a nest of babies in her hutch!!!?!? Is it possible she has bred with wild rabbits (plenty of them in the field behind us)??? If so will the kits be ok??? Also, we have cats which never bothered the rabbits as they were nearly the same size when we got them however and the rabbits frightened them away but I'm really worried the cats will see the babies... so what do I do??? Can anyone offer any advice??

they CAN'T breed with wild cottontails, but if you have a wild domestic rabbit running around that'll be your culprit.

The kits will be fine if she takes care of them.

What to do about the cats I can't advise you. the danger period will be at 4-5 weeks when they start to wander away from the nest to seek out their own lives. Or momma shoos them away as she's got a new litter on the way. (she's most likely preggers already).

Thanks for getting back to me! We live in the countryside and only have 5 houses near us, none of which have ever had Rabbits. I'm not sure what breed the ones in the field are, I'm in Ireland??