Poppy seems to have adopted one of Tilly's babies-HELP!

Hia
As you may already know, Tilly gave birth to 3 kittens 2 weeks ago. She's been doing absolutely fine although she's not in the box with them as much as she was in the beginning.
Is this a natural process??
She is feeding them and they seem to be gaining weight nicely.

Poppy my other cat was spayed 6 days ago. I went upstairs about an hour ago and Tilly was in her box with two of her babies and I got the shock of my life as Poppy was sitting just outside the box cuddling the other one!!!
Tilly didn't seem to object, but I'm very concerned about this odd behaviour.

What's going on?? I'm really concerned

Here's poppy with the baby



I've since put the baby back in the box with the others, but poppy is keeping watch like a hawk!!

Awww sweet pic ........

As long as Poppy isnt harming the babies, they will be fine. Cats can raise the kittens together as long as Tilly is nursing them and they are continuing to gain weight. And since Tilly isnt bothered by Poppy, then its fine.

My Mother cat didnt continuously lay with her kittens either. She would feed them, clean them and then she wanted some time to herself or with me. But would always go back to check on them.

In a feral colony often times queens will care for and nurse the other kittens. Be sure that the place where the original family is at is large enough to accomodate all the kittens and the mom with mom having room to move around in. If she moved the kitten out of the box, there might be something wrong with it, but there is also a possiblity that your other female snatched the kitten. Make sure the kitten is getting the advantage of the milk bar, if mom denies it food you will have to bottle feed. If she pushes the kitten away, then something is probably wrong with it.