In my past life as a police officer, I had to assist a neighboring department in dealing with a very similar situation. The home was condemned because the cats had gotten into the walls and cat urine and feces were all over the drywall and supporting studs as well as the underflooring wood and beams. It was a major health hazard and there was no way to refurbish the home due to the extent of the damage the cats had done. The house had to be bulldozed.
If she was attempting to go back into a condemned home because feral cats kept showing up there and she wanted to feed them then yes, she was trespassing.
Were the cats charged with anything?