I would say no.It is a working farm and you are working this weekend.Postpone to another time.It will be hard enough keeping the kids under control .You might lose the sale,but shoot they can go to an educational farm for a farm experience.That is what I do...take the kids to a edu farm.Most people do not let strangers on the farm for bio security reasons.
So I vote no to this weekend visit.That or you get them in and out FAST. Box up the chicks and all before she comes.Sounds like she wants a tour though.Just say your farm is not a touring farm.That it simply would not be safe for children. Many people sell chicks, and touring the farm is NOT an option.Buyers are OK with that,Shoot,soome people refuse to even disclose their location,and instead meet up somewhere.It is not just bio security you need to worry about.
Best wishes whatever you decide and healings for dad.
U always know just what to say... U deserve an award.