To keep mosquitoes, ticks, and other external parasites off your rabbits, you can take the following preventive measures:

1. Housing: Ensure that your rabbit's living area is clean, well-maintained, and free of standing water, which can attract mosquitoes. Keep the area properly enclosed to prevent access by ticks and other pests.

2. Screens and Netting: Use fine mesh screens or netting on windows, doors, and ventilation openings in your rabbit's housing to prevent mosquitoes and other flying insects from entering.

3. Natural Repellents: Some natural repellents, such as neem oil or diluted apple cider vinegar, can be used on the rabbit's fur or in their living environment to deter mosquitoes and ticks. However, it's important to use these products in moderation and consult with a veterinarian to ensure they are safe for rabbits.

4. Regular Grooming: Regularly groom your rabbits to check for ticks or other external parasites. Use a flea comb to carefully remove any visible parasites. Pay special attention to areas where parasites are likely to hide, such as behind the ears, around the tail, and in the armpits.

5. Environmental Management: Keep the surrounding environment free of debris, tall grass, and overgrown vegetation, as these can harbor ticks and other pests. Regularly mow the grass and remove any potential breeding grounds for mosquitoes, such as stagnant water.

6. Veterinary Care: Consult with a veterinarian for appropriate preventive measures, such as topical or oral parasite control products that are safe for rabbits. They can recommend suitable options based on your rabbit's age, health, and the prevalence of parasites in your area.

Remember, prevention is key when it comes to protecting your rabbits from parasites. By implementing these measures and regularly monitoring your rabbits for any signs of infestation, you can help keep them safe and comfortable.