Just an observation or two.Since frosted greens can cause serious issues of chilling for the stomach and intestines,I wouldn't use ice cubes personally.Given that they;ll probably melt quickly anyway they will be of little value in reality.The frozen water bottle works very well and they love to cuddle up it.I also rig up an electric fan( making sure that any plugs,connections to extension cable drums etc,are covered to avoid accidental water splashes or unexpected rain,and that the plug is connected to an emergency circuit breaker device in case of anything untoward happening.This works very well and distributes cold air around the cage.It goes without saying that the fan and cables are outside the cage,not inside it-for obvious reasons! By the way, I read many years ago,and it was taken as a fact in many books on rabbit care,that giving wet greens was a bad thing and casued diarrhoea and gut problems.I believed it myself and have told others about it in the past,until my vet pointed out that if this was the case then wild rabbits which ate wild plants full of dew or rain water after a shower,would have problems.He was of the opinion that it was a myth,and a misunderstanding,since the real problem was not with the water,but with greens from a refrigerator or from the ground in Winter ,which had been frosted and given while still in this condition.Seems to make more sense,and I have made sure that I never feed anything with too much a chill on it.