Is there any way you can separate the crawlers form her at certain times in the day?
also I try to position myself well to see all the children and step in before something happens
I know it's hard as I take care of 4 children under the age of 3 years so it has it's busy times the high chair or a stroller is always good to have as a time out at this age
Good Luck - it is good to get feed back form your hubby