I agree with Logan. These sound like young kids if they want you to hold them and what are these parents thinking? Don't they know these kids can get all sorts of diseases from being in an environment like this? Almost sounds like they care for the wildlife more than they do for the kids.

But I think you should go if you enjoy it. Try and distance yourself from the kids at first until you get to know the parents a little better and then you might feel more comfortable saying something.

Also, you might be able to help the kids by saying something like "Come on Johnny, lets go wash your hands before we eat that cookie, ok?" So it might be a good thing for the animals and for the kids if you helped out - and also a good thing for your marriage since your husband will be happy again.