Lop rabbits simply have the floppy ears.
We had angora rabbits when we were kids. Lots of hair meant lots of brushing and combing to keep the rabbits free of matts. They breed like rabbits, one batch after another. Unfortunately they all got Myxomatosis when it was released and our neighbour rang their necks when they were dying. It was pretty horrible watching them die from the virus
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Keep them in a hutch with a wire floor so their poop and pee goes down below the cage and they aren't standing in it. Rabbits will use a litter tray in a house and you have some kitty litter, clean sand or sawdust in a plastic tray, add a bit of bunny poop and encourage the rabbit to use the tray. Once it starts using the tray, keep the tray there.
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Keep their cage covered in flywire to stop mozzies and flies getting to them. Mozzies spread Myxomatosis and flies spread Calicivirus, both have a 100% kill rate on domestic rabbits and there is no cure and no vaccine to protect them.
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Keep the rabbits cool in summer and warm in winter. If the temperature is nice for you, it's nice for the rabbit.
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If you have a male rabbit, get it sterilised to reduce aggression. Male dwarf rabbits in particular have way too much testosterone and regularly bite and attack their owners when the rabbit matures. Sterilising them makes them much nicer pets and less likely to cause problems. Females don't need to be sterilised. I always found female rabbits to be nicer natured.
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Feed them a dry rabbit pellet and rabbit mix, as well as fresh fruit and vegetables. Apple, pear, plums, carrots, etc are all good for them. They need the hard dry pellets and carrots to help wear their teeth down because their teeth grow continuously. If they don't get enough hard food or some wood to chew on, their teeth can grow too long and you will need a vet to fix the teeth.
Do not give them citrus, onions or onion relatives (leeks, spring onions, shallots, garlic) and no potatoe.
Avoid lettuce and give them dark green leafy vegetables like spinach, silverbeet, kale, etc. If the animals have been on a dry food diet and not had any fruit or veg for more than 2 weeks, only offer them a small amount of green leafy vegetable to start with otherwise they can get an upset stomach and end up with diarrhea. Once they are eating fruit and veg and been on it for a few weeks, they can be given more. They will also eat grass but make sure it is free of chemicals and dogs, cats and other animals haven't peed or pooped on it.
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You can deworm the rabbits once or twice a year but domestic animals are usually pretty clean. If your rabbit is eating and acting normally but losing weight, it probably has intestinal worms and you can get dewormers for small animals from most pet shops, or talk to the vet.