What I do first is a belly massage to get things moving, or putting the rabbit on my leg when sitting and rocking the whole bunny. Or making them hop around. Also syringing water every few hours if the rabbit doesn't drink, I add simethicone (Baby gas drops) to it (20mg, 2-3 times per day) just in case. If bloat is the issue, I start force feeding small amounts pretty soon, this year one girl had a blockage from too much ingested fur, vet gave her 1ml of paraffin oil in the morning, I did the same around noon and started force feeding in the evening, massaging her for 10 minutes every 2 hours. Vet also gave some appetite enhancer.
Most times they started eating on their own pretty soon once they had a few mouth full of food, but somehow it looked like they needed that nudge.
When of mine had gas (3 times), or something like that it was sitting loafed up and obviously in some pain, massaging brought relief.
In the case ofthe block the rabbit seemed relaxed, flopped, just not caring about food.
This is just my anectotic experience, not general rules or so, when one of my keepers or pets stops eating for a day I'm off to the vet - costs just around 50€ here, can live with that.
