Rabbits cannot be separated from their mother until they are around 8 weeks old. Are you sure your rabbits are 4 weeks old, and if so, are they still with their mother? Clarification on age is important.

Hmm, are they outside? If they are outside, they can get heat-lazy and not drink much water, if so, I would recommend bringing them inside to cool off and be overall more healthy and happy. 🙂 If they are inside, I don’t know what else it could be. Just thought I would ask that question for that was my first thought.

6 to 8 weeks is the usual range, but 8wo is typically what we see most often.

Water bottles, while widely advertised, are actually not the best for rabbits. There have been studies that show that rabbits drink less water from a bottle than they do when given a water bowl. This is because it takes effort to drink water from the water bottle — the animal needs to arc their neck up and constantly stimulate the metal bearing/ball back and forth so tiny amounts of water come out. There is also the chance that air bubbles get caught and the water bottle isn’t actually working, so rabbits do not get water. Especially for small and young rabbits, it’s possible that the bearing/ball is too heavy/effortful for them to shift efficiently, so they don’t see it as a water source at all. Lastly, water bottles can grow a lot of bacteria/mold because it’s hard to clean them effectively.

In short, try giving them a water bowl instead and see if that helps.

@Rusti

Is there a way you could bring them inside? House buns tend to form better bonds with their owners, plus they have better conditions. It is very good though how you are closely monitoring how much water they are drinking, that is good. 🙂

If there is no way you can bring them inside, then a cooling tip is frozen water bottles, and fans help greatly, too. Agree with @Wick, water bowls are better, don’t think that you are doing everything wrong though, we all are trying to do what is best for our buns. 🙂 I don’t think that there has ever been one member come on here knowing everything to bunny owning, if there has been, it would be extremely rare.

Wishing you luck!

Rabbits can overheat when it gets over 80F, so it’s good you brought them inside. Frozen bottles and tiles work well, but with bunnies that young I agree they should be inside.

Agree with HipHopBunny, maybe you could keep them inside permanently? 🙂