Rabbit Heavy Breathing, Open Mouth (video)

Question
Hi Dr. Krempels,

Thank you in advance for taking the time.

I have a 6yr. old rescue (literally rescued from some nefarious teens about 6 years ago), he is a neutered male, about 6 1/2 yrs old - his name is Pipkin or Pip for short.

He's always been in great health, and has only seen the vet for his initial check-up and neutering.

Over the last few weeks, I noticed that when he breathed (in both an excited and restful state), it seemed much heavier, and his head 'rocked' forward and back with his breathing, whereas up until now only his diaphram moved when he breathed and his head stayed still.

I didn't take him to the vet simply because I assumed he was 'getting older' and this was normal behaviour.

He has been eating well (pellets, timothy hay and his obligatory cranberries), and I've only noticed a slight decrease in activity, which again I attributed to age.  Every night he comes out with us for a few hours and he still seems to 'explore' and bink.

Yesterday I decided to do some research, and noticed that some people were stating that if a Rabbit is breathing though his or her mouth, its a problem - and Pip is doing just that.  

I recorded him with my phone and uploaded it to YT (technology!) - I turn on the light at the end.  

https://www.youtube.com/watch?v=6nGvoYet528

Should I be worried? Is Pip just getting old?  I can't really think of any other differences except that for the past month or two he will sometimes 'hack' or 'cough' when eating hay.  Just one quick hack, maybe twice during a 20 minute feeding. He just goes right on eating. Digestion seems fine.

Again thanks for your time!

Jared

*You may get this questions twice as I tried to add it with my phone with no certain success.

Answer
Dear Jared,

This is a very serious condition, and Pip needs to be seen by a rabbit-savvy vet ASAP.  Mouth breathing means respiratory distress, and that can be caused by a respiratory disease (nasal congestion, pneumonia) or a thymoma (enlarged tumor of the thymus taking up the room that the lungs need for breathing.

A radiograph will reveal congestion or a tumor, and the vet can then give you treatment options.  But please waste no time.  A condition like this should be addressed by a vet immediately, not by anyone on the internet (me) who cannot even see or examine the rabbit.  Find a vet here:

http://www.rabbit.org/vet

I hope Pip will be fine.

Dana