My bunny has been pooping connected poops (see picture). I sometimes see a couple of these when cleaning the litter box. Is something wrong? What causes this?

My bunny has been pooping connected poops (see picture). I sometimes see a couple of these when cleaning the litter box. Is something wrong? What causes this?

I think there are two concerns here (assuming colour is accurate)
1) the connection appears to be fur which suggests the rabbit has an increased chance of going into stasis/gut immobility from wool block
2) the colour of the faeces is quite dark, and maybe a bit small which can suggest a poor diet (unless this is an exposure issue with the picture?) a normal rabbit poo should be a golden colour e.g.

as the picture suggests, size is also a consideration but this will vary with breed
overall i'd suggest reviewing the rabbit diet and in particular making sure it is having enough hay (it should be ~90% of their diet). You could also look at grooming your rabbit so that it isn't eating so much fur.