I think leaving them at home is the best thing for them !    They are familiar with their surroundings, so they won't have anxiety being boarded...Anyway, has anyone who suggested boarding them ever looked at the places?   I checked out a 'spa-style' place....The closet with a window in the door was like solitary confinement !    It smelled and the dogs looked confused !
I wouldn't crate you lab, how cruel for those many hours during the day and at night!   I would leave them in the house with all the bedroom doors shut....
Whenever I surprise my 3, they are usually sleeping next to eachother and that's what yours will probably do....
I do advise though strongly, that when your MIL lets them out, she watches "HOME, SWEET HOME".....
