Some screenshots from Kitten Lady's 2019 video titled "I Went KITTEN SHOPPING!" in which they discuss the Herb Garden kittens who had to be kept separate because they were sucking on each other. These kittens were without a mama cat for so long they tried to nurse on each other, by sucking each other's genitals (usually those of the male kittens). This is a behaviour that may stick even after they start being bottle-fed again. It is very dangerous both for the kitten sucking (because it will make the other kitten pee, and the sucking kitten will ingest urine); and for the kitten being sucked on, as it can lead to deformation of their genitals.
The solution to this behaviour is to keep the kittens separate when not supervised. They can have play time together with supervision after feedings, but need to be separated again once they go back to sleep.
The behaviour usually disappears once they're no longer bottle fed, though I've had couple of cases where it persisted after, when a kitten is looking for comfort (similarly to how kittens can continue to suckle their mama for comfort after they've been weaned off of her milk). As a foster parent, my only solution to persistent sucking is not to adopt that particular kitten out with her brothers.
I've had a couple of litters that engaged in sucking (once two litters of a similar age at the same time) and it can be very stressful. If you're dealing with this and you're struggling, make sure to reach out to your shelter for advice and additional material. I had a lot of trouble making sure all the kittens had a heat source (which they need in the first few weeks) and keep them from each other once they were older and needed more space (but were still bottle fed). Luckily these particular kittens stopped once bottle time was over and they were able to be together 24/7 again.
[ID: 6 screenshots with subtitles on from Kitten Lady's Youtube video "I went kitten shopping!".
In the first screenshot, three women, with Kitten Lady on the right, are talking to each other. In the next five screenshots, Kitten lady is holding a black baby kitten, while another person approaches with a cat carrier, opens it and Kitten Lady puts the black baby kitten inside.
The first screenshot has white overlay text that says: "The herb garden kittens were separated due to sucking (nursing on each other) which can be harmful for the babies."
The 2nd to 6th screenshot shows the following subtitles for the dialogue:
"How long have they been separated from each other?"
"V: We- They came into us nursing on each other, so they cam [sic] iiinn..."
"KL: So they don't know each other?"
"V: They… They know each other- They see each other because they get to be together while they're being monitored,"
"and then when they go back to bed, we separate them out."
