How do I keep guest dog from eating my dog's food when my dog is a grazer?

My honest opinion will not be what you want to hear. All dogs that stay at my house, regardless of their feeding pattern at home, get scheduled meals. (I have a beagle and grazing does not work because they will eat themselves into oblivion.)

For the 9 days that Milo stays with you, I would have Baby eat on a schedule as well. Assuming you feed Milo at, say, 7am and 6pm, you will also feed Baby at those times.

Estimate how much food Baby generally eats in a 24 hour period (or check the package for correct feeding amounts) and divide in half. Give her 10 minutes or so to eat at mealtime. Keep whatever s/he doesn't eat in the morning and add to the evening feeding. She'll quickly realize that she needs to eat when breakfast/dinner is put down. I promise she won't starve.

Baby will not be harmed at all and you will get the booking!

PS - I find that sometimes I need to physically sit next to my guest while they eat; if I walk away they stop. Jut giving you a heads up.

Most dogs are going to eat your dog's food if it is left out. When I host dogs who are used to free feeding, I give them about 15 minutes to eat their food, with me watching, and if they don't, then I pick it up and will try again later. I can't leave food out because my dog will eat theirs as well. If you are going to host other dogs, you are going to encounter this situation frequently.

As Carmen said, the free-feeding dog is not going to starve and should adjust to the new meal times.

I agree with pulling your dog's food so the Rover dog can't get it. That is what I had to do because my Carley-girl is also a grazer. I felt so guilty at first. She's 11 years old so all this Rover-business has been an adjustment for her all the way around.

However... I came up with a win-win. I add a Tbsp of plain yogurt, cottage cheese or chicken broth to her food now so she'll it it right away. It's kind of her reward for putting up with all the other dogs being in her space. She does run around with the Rover dogs sometimes so I think she burns off that little bit of extra calories.

The only drawback is when the Rover dogs leave she thinks she should still get the add-in. I've stopped doing that though because I don't want her hips getting too heavy AND it needs to be special when the other dogs are here.. She eventually got with the program.