Rooster comb turning purplish

Yesterday I noticed that my roosters comb had a faint purple- blue tinge on the edges. It almost looked like dirt. He's been acting perfectly fine, so I'm not sure what I should do!

He's a 17 week old buff orpington. He lives with a 17 week old buff brahma hen.

What could be wrong with him?

Then I looked again and it was gone! The comb was fine. Than 5 minutes later the purple was back.

In my experience, small amounts of occasional comb-darkening are normal. Especially at the back (blade) of the comb. My birds with larger combs will sometimes get this after exerting themselves, or if they are very excited and "flushing". Purple tints to the comb have to do with bloodflow and oxygen levels in the blood, so it makes sense that on occasion when their bodies are using more oxygen in other areas, the comb (which, to a chicken, is much less vital than other parts of the body) loses some of the bloodflow first. Was your bird previously very excited? Simple things can be exciting to a chicken, such as feeding time, or the appearance of a "Food Human", or activity by other birds. For roosters, other things may be exciting, as well! He is at that age.

If more of the comb turns purpleish, for longer periods of time and/or more frequently, that would be a cause for concern. Observe this guy and let us know what you notice! Check his breathing as well. If his comb goes overall more purple, or does it more frequently, be sure to observe him closely.

Nambroth has given some good advice.

I, too, have noticed that some of my birds get purple combs at certain times. In particular, a Wyandotte male. Whenever he gets excited over hens (normally, he lives alone next to other males, but during breeding season, he gets some hens), his comb often turns purple. Within a few minutes of more relaxing activity, it turns to the normal red coloration.

I had just let him out to free range for a bit, so he got super excited and flew across the lawn. That must have been it! Thanks for those helpful responses!! I'm so relieved.