Too many types of grain?

I frequently see recipes with a variety of malt, usually as each contributes a desirable element (body, head retention, etc.) but not so much with different grain types. The reason for my question: I have this canister of organic multi-grain cereal that is made up entirely of rolled rye, barley, oats and wheat. Was going to toss it all into the mash, but didn't know if there are any conflicts.

(honestly, I'm never going to eat it otherwise)

sure you can. there are plenty of mult-grain beers. sounds like a fun experiment.

just make sure to have enough base malt to convert whatever may be in those grains.

Mash it pound for pound with 2-row and you'll have a full-bodied, high head retention, spicy ale. Or something like that.

I have a similar bag of "cereal" and have been wanting to do this as well. Let me know how it turns out!