I think the answer depends on your chicken. Some broodies get off the nest and eat and get some exercise a lot more than others do. They're also even more prone to lice/mites when broody. At the least I'd check her thoroughly for this, and see if I could tell whether she's lost weight. Maybe carry her a good distance from the coop and see how she walks back. Check her breast or keel bone and see if she feels thin or bony to you; compare her to your others, if you have other Silkies.
I've given new store bought chicks to a broody who's been on the nest a month or so, just to get her off the nest and moving again. I did give eggs to a long time broody once, when I was new to all this, and it worked out fine, but she would get off the nest and get outdoors any time I went to the coop, so she was eating and getting exercise fairly well.
Another thought is, breaking a broody works better on some than others. It may be that eggs or chicks are the only way she'll stop.
