Questions

My beloved backyard rabbit Marshmello died on Friday. Not sure at all what happened. I watered weed killer onto my lawn after the Home Depot guy said it should be OK. I told him my rabbit lived in the backyard (with garage for shelter and a heat lamp for warmth as needed. Not sure if this was an issue or not. Marshmello does eat grass and other plants in my yard that got sprayed. Around that time, I noticed him hunkered down with his eyes closed, sitting very quietly. I thought he was looking very content since the weather was very nice. After a week and a half, he lost his appetite and it was then that I became concerned. With him totally not eating for the last few days, I was afraid for his life. The next morning, he was hardly moving and was a bit limp. I stroked him under his ears at the base of his neck. It was very warm and I felt what seemed like something or fluid rushing from the spine past his neck into his head/brain....so that's why I was wondering if he was experiencing that same sensation when I saw him hunkered down, still, with his eyes closed in the past week. I know rabbits get viruses out of the blue and die for unknown reasons. But my big question is if anyone else has experienced the warm neck and fluid-rushing sensation in their rabbit at all.

I do not know anything about the warm neck and fluid-rushing. What I do know, is that whenever a rabbit stops eating, he needs immediate help. A rabbit not eating and sitting in the shape of a football (hunkered down) is in pain. If it is caught early, simethicone will often take care of the pain and get him eating again.

If a rabbit goes 12 hours without eating, he should go to the vet. A rabbit's gut must be in constant motion. They are not like other animals (or people, for that matter) that can go a few days without food. They must eat.

GI stasis is the term used to describe when a rabbit's gut stop moving. Gut motility meds would have been prescribed by a vet (along with hydration and pain killer). GI stasis has many potential triggers. The weed killer could have caused a problem. But it could have been something else as well.

One thing to bear in mind too is that domestic rabbits have lost their ability to know which plants are safe to eat. Perhaps there are toxic plants in the area? Pesticides, weed killers, fertilizers-- none should be put on grass or plants that a rabbit may ingest.

Sorry about your bunny. If you ever decide to get another, perhaps it would be better to house him indoors. Just browse around this site to see how people keep them indoors:
http://www.rabbitsonline.net/showthread.php?t=87073

Rabbits rarely get viruses if you are here in the US. I'm afraid to say that the home depot guy was wrong and your rabbit likely got poisoned. Rabbits don't just walk on the grass after things like weed killer have been applied, like cats and dogs would do. They are herbivores so could easily ingest the toxin from eating the plants that it's been applied to, and so ingest much more than an animal that might just lick some off it's paws. You really should inform not only the employee that gave you this information, but also the manager of the store, so that they do not continue to give out this false and dangerous information to other rabbit owners.

Why those symptoms occurred, would be related to the type of poison that was ingested.

I'm very sorry that you lost your bun.