Having owned a border collie I can say they are (in general) not the best dogs to have around young kids. They tend to want to heard the little ones and may sometimes nip at ankles if order is not maintained. To an extent this behavior can be influenced by how much work the dog is getting, Genetics too - believe it or not some have a greatly reduced herding instinct. Also, a farm is not essential but daily work/activity is - flyball/Frisbee agility etc work well to.