Hi Kathie, thanks for the question.

This question may be influenced by how we envision mulch. Mulch can be organic, inorganic, or even living plants. It is possible that deer are attracted to certain mulches that can provide support or indicate some sort of food source. This would include straw, leaves, fresh grass clippings and living mulches. There are some mulches that are considered deterrents such as straw, cedar chips, and pine needles but there is little research to support this. Deer are more likely to be attracted to certain plants. There is some suggestion that a more diverse plant selection with plants less desirable to deer combines with more desirable plants is less attractive. It is important to remember that when deer are hungry, they will eat what is available. Check out the following links:

https://www.canr.msu.edu/resources/smart_gardening_to_deter_deer

Deer_resistant_plants_MSUE_E3042

I hope this helps.