It totally depends what kind of mushrooms they are. "Organic white" does not really identify them. For example, my store sometimes sells white
Agaricus bisporus, the familiar white mushroom many people eat, but you know, the deadly
Amanita virosa, also known as the "destroying angel", is also white and organic, although you would never see it for sale at a store - at least, I HOPE NOT. Are you feeding something you bought at a store, that was meant for human consumption, or are we talking about something growing in your yard or the forest etc?
If you are feeding something you bought at a store, that was meant for human consumption, you are safe. If you are feeding something growing out of your yard or the local field etc, and the only thing you know about it is that it's white, that may or may not be safe.
And in fact, animals can safely eat wild mushrooms that are not safe for human beings to eat. One of the things one learns, when collecting wild mushrooms, is that just because some animal was eating it, that does NOT mean it's safe for a person to eat! If you are talking about a wild mushroom growing somewhere out in the wild, I would caution you not to pick it or eat it, UNLESS you have the help of a very experienced person to help you with identification. If we are talking about something you bought at a store, that was meant for people, you are fine.
Sorry to be so cautious but I was not real clear what you meant.