The U.S. Immigration and Customs Enforcement said the three ate some of their Monday breakfast but remain under medical observation.
The wife of one immigrant said in a statement over the weekend that her husband lost at least 20 pounds but said he won't stop protesting until federal officials meet their calls for better treatment.
Immigrant-rights activist Jessica Ramirez with Latino Advocacy says the group has learned that others at the facility have recently joined in the hunger strike. An ICE spokesman declined to comment.
The strike began March 7 with hundreds of participants refusing to eat to call for an end to deportations and better treatment.