Hi, I’m not too sure about the ‘best material’ to use for your rabbits’ home but what I do know is that your situation (starting off with two bunnies and ending up with many more baby rabbits) is unfortunately very common due to misinformation and lack of education about rabbits. I think that you have done the right thing by coming to a platform like this one though in trying to gain knowledge on the situation. The first thing I would say is that you need to separate your rabbits into male and female ASAP. This includes creating at least two separate safe and secure areas which are not in touching distance of each other to prevent further unwanted litters. It is also vital that you must spay or neuter all of your rabbits ASAP (providing the males are at least 4 months old and the female’s are at least 6 months) to ensure that this doesn’t happen again. I don’t know how old the baby rabbits are but if they are 8 weeks or older then you must look out for fighting between them as this is likely when they are not spayed or neutered due to high hormone levels which cause territorial behaviour and often leading to aggression. If you cannot afford to meet the costs of spaying and neutering all of your rabbits or provide suitable accommodation and space for the rabbits then I would strongly suggest going to your local rabbit rescue and see what they recommend and if they are able to help you in any ways. I really hope that you take my advice into consideration as it is truly fundamental to the welfare of these rabbits and ensuring that this situation does not escalate any further to the point where it is unmanageable. If you have any questions whatsoever, feel free to message me or reply to this comment and I would be happy to help and answer any questions you may have.
