In my opinion, yes. They get aggressive once they have babies and might kill each others litters. It's best to separate them. I know some people have them in colonies and it might be different for them, but in general they should be separated before kindling.
I tried to tell someone who had like 6 females and one male about this around november she didn't listen and guess what she found 2 litters of dead babies. she then thought hey, I will separate the male but by this time all 6 females were pregnant, now some babies survived from the 6 litters but not all. and then I am not sure what happened but they all got Cocci and as of now I have no clue how many of her rabbits died.
they get aggressive when babies come in to the mix and leaving the male in with them is a huge chance that he will kill all the babies. other females will do the same thing. if you want the babies to survive please separate. I took 4 rabbits off the lady I was just talking about. mine survived and I brought them in from the cold, she had them in a stall in a barn with no top, and well barn cats tend to get in there and have been known to kill some babies, chew some up and then leave them there. I know because I saw one of them the day I went to pick up my 4 bunnies. If I hadn't taken in these 4 they would be dead already.
Yeap seperate PLEASE sooner the better. - Depends what your doing with the Rabbits. - DO get the babies sexed as soon as you can and seperate the males as they can start to reproduce again at only 6 weeks. You know the saying Breed like Rabbits - IT IS TRUE!!!!!!!
Putting bucks together is a bad idea over all. I've seen some pretty horrendous injuries and deaths in bucks that were kept together. If you've ever seen Watership Down you will know what I'm saying and that's just a cartoon. Putting more than one buck in with does is also a bad idea because the males will fight for dominance and more than one doe and you also get dominance. That's just the adults fighting. Once kits are born then you risk bucks and does killing kits. Although I've seen more deaths from does stealing kits than just outright attacking. So I stick with the rule of one bunny per enclosure unless they are breeding and once done breeding they are then separated.
I use to breed rabbits for 4h and FFA. Just look for hutches that let you separate. I use to keep males separated in one area and then put them with whatever female for a day or two. I kept logs of which male was with what female and what time to expect babies. I made sure nesting boxes were in there giving them plenty of time to pull their fluff out and line the box. Keep them separated , so each female tend to her own young without another female around. They tend to eat babies. I used to give liver to the, before birth.