My woman and I recently brought home a rescued bunny named baxter.  Baxter has been super social and sweet to use.  Playing routinely on the bed and on the floor with us.  He lets us hold him without struggling in the least.

Something changed or provoked him this weekend.  Nothing out of the usual happened but Baxter is running away from his mommy, hiding in his cage and generally being a brat.  She says nothing out of the ordinary happened but in the period of the day he is now the opposite from how he was when we got him.

I would like your opinions on possible help, strategies, etx

Baxter is a year old.

thank you

Welcome BaxtersDaddy!  

So  few questions first:   

1. Is Baxter neutered?

2.  Was your girlfriend around any other animals?  She didn't have to be actually petting them.

3. Did she change anything scented  -  perfume, body lotion, hair products, laundry products?

4.  How long have you had Baxter?

5.  Does he become aggressive at any point?  If so, when exactly?

For some reason I missed this post.  How is Baxter doing today?  Has be improved?

I have a few more questions BaxtersDaddy, welcome to the forum! 

My overall suggestion is to try and sit on the floor with him and give him a treat ot two, check the area around his cage for anything out of the ordinary.  You're going to need to be a detective, below are some suggestions/tips.

Has his diet changed at all other than him not eating? Any new foods? Any new brands? Any change to anything for a bunny is traumatic and they will react this way as well.  It could be the smallest or simplest thing, a change in litter, a new bowl, a new carpet deoderizer, a new fan that makes noise, a neighbor that has since started working on cars and revving the engine, a new aerosol for the bathroom, a new can opener that is different sounding than the last one, heck my two react this way when I am cooking any type of meat or fish. It is not always a human-related product that does this.

Is his cage near a window? Predators such as a cat, fox, raccoon, dog etc. can really frighten a  bunny and change them in this manner. 

Has his cage moved? Bunnies generally like their home to stay where it is, I know that mine do. 

Has anything new entered your house at all?

Have there been any humans fighting or yelling at or near him? Bunnies react to the environment around them too, as they are quite sensitive.  Have you checked around the house to see if he has chewed on anything like an electrical cord or any thing else around the house?

Are there any children in your household? What are their ages?

I hope this helps!

Is it possible he was fed something other than the usual by a human?

Has he refused his treats?  If he has, this would be a sign to take him to the vet.  If he has not taken any water, take him right away. He may be dehydrated and something wrong internally could be going on.

Is Baxter still active now?  If not, take him to the vet. Extreme lethargy is usually not a good sign.