How do I get my dogs to eat from separate bowls?

I have two chihuahuas. They are 15 months old now. Ever since I brought them home they have been sharing their food, however; lately I have noticed that one dog is getting heavier than the other one. They both look healthy, but there is a pound difference between them. I am worried that the thinner one isn't getting enough to eat. She is more timid than the other one. The bigger one dominates her in every way. If I put down two dishes they still go to the same one. I feed them dry food, and I am not home all day to watch them so I don't know who is eating what. Any suggestions?

Two female dogs of the same age can often be problematic with fighting and dominance issues. If you are leaving food down all day, there could be serious problems with fighting over it as they get older.

You can separate them. Put up a gate and keep them apart, each with their own food, during the day.