I almost didn't say anything but. Yknow what. No. I'm saying something. Scout here has a massive following and I'm not going to stand idly by as they spout off things they have no experience or knowledge in. Rabbit breeders already deal with enough hell from a public that doesn't understand what we do or why we do what we do - we don't need even more of it from a blog that claims to be an animal welfare blog.
Think about how often rabbits are able to breed. Think about how many kits are in each litter. For many breeds, 6+ kits in a litter is the ideal. Even if a person only breeds their rabbits twice per year, that's 12 kits per rabbit every year. Ideally, a person would have at least two does - that brings our total up to 24 kits per year on average. This isn't even counting the breeds that average around 9 kits per litter (that would be 36 kits per year).
Now think about space constraints and financial constraints. People only have so much space for only so many rabbits. Even if they only breed once a year and only have one doe, that's still 12 kits. That's 12 kits that are going to need cage space. Depending on the breed, those kits won't reach a reasonable meat weight until well after they've been weaned, and by that time, bucks need to be kept in separate housing. If a person doesn't have the capability of attempting to keep their does in a colony or tractor, they'll need to keep each individual doe in a cage. That means that person who only started with two rabbits would need to have a minimum of 8 cages in order to grow those kits out, maybe more depending on how fast those kits grow and when they rebreed their doe. 8 cages can cost upwards of $400 if they're new, and still a similar price even if they are used.
Now imagine a standard rabbit breeder, who would have likely at a minimum at least 4 does and a buck. 4 does producing an average of 48 kits every year. That means a breeder would need an absolute minimum of 29 cages. That's $1,450 spent just on cages. It's a huge investment to have a large amount of rabbits, and it's a huge investment to be making on kits that are obvious from birth that they will provide very little if any benefit to their breed as a whole. That's not even mentioning all of the extra feed costs (especially now with inflation being so bad) for feeding all of those extra rabbits.
Some breeds have very specific markings - like the rabbit in my pfp, for example. These markings are often able to be determined if they are mismarked or not from a very early age. Those mismarkings need to be culled for. In order to avoid the extra costs associated with having extra cage space you don't actually need just to grow out a bunch of kits that you already know won't cut it as breeders, the only other option is to sell those kits after weaning. No breeder is going to want them, so what are you going to do? You'll sell them as pets. CONGRATULATIONS - You've just contributed to the problem of rabbits in shelters, feral rabbits, rabbits suffering in pet homes that can't take care of them. Imagine even just two kits from every litter being mismarked and needing to be culled - if you've got four does and 8 litters, that's 16 young rabbits that will need to find homes in just one year.
And so, in order to avoid those things, a good breeder who knows what space constraints they have, knows what financial constraints they have, and doesn't want to contribute to the problems that ARAs constantly say we contribute to, may very well choose to cull kits in the nestbox that they know won't make it as potential show or breeding stock.
Just because a kit is killed so young, that doesn't mean it has to just get tossed aside or that it has no use. Talk to my cat about that - she absolutely loves a good whole prey raw snack. Or talk to any dog. Or any snake. Or large lizard. Maybe go talk to the raptors at a raptor sanctuary, or small carnivorous creatures at the local zoo or wildlife sanctuary.
None of this is even mentioning the benefits nestbox culling has on the doe and the other kits in the litter. Does may often have more kits than they can reasonably care for. Sure, some can be fostered by another doe, but why put the strain on another doe for kits you know won't make the cut anyways? By nestbox culling, it reduces the amount of stress on the doe. It also makes it so the kits that do have a chance at being utilized for breeding get a more ample supply of milk, and therefore all grow to be bigger, stronger, healthier, and overall more robust.
Nestbox culling is an act of animal welfare. It ensures that the breeder isn't trying to care for more animals than they can reasonably/financially handle. It ensures that animals aren't going to end up in shelters, or being free somewhere, or suffering in homes where they aren't being cared for properly. This is extremely important in species that have a large amount of babies in each litter, which is something that I know can be very hard to understand when a person either only has experience with species that have very few babies per year, or has no experience with breeding animals at all (looking at some of y'all in the notes).