Can a cat mom move her 7 week old kittens?

[td95]

One of the stray cats I am taking care for gave birth to four kittens seven weeks ago in my basement. One of the kittens didn't make it, but the other three of them have grown up pretty fast and seem to be very healthy and happy.
However, few hours ago I went to their place to feed them, and noticed that none of the kittens was there. At first, I thought that they must have had been hiding somewhere, as they were still too young to climb and leave through the window that I keep open for their mom to come and go. However, that wasn't the case. Their mom is behaving normal and she is not looking for them, which seems weird considering how caring and loving she always was.
Is it possible that the mom herself moved the kittens to some other place? I have heard some cats do that to their newborns, but I didn't realize that they can do that to kittens that are almost two months old. I don't even want to think that she could eat them, and I think it's very unlikely considering their age. They were also very safe in their prior location.
I just went outside to look for them, but they were nowhere to be seen. I really have no idea what had happened there.
Does anyone have any idea?
Thank you in advance.

 

[Sarthur2]

I think it would be difficult for mom to move 7-week-old kittens. Are you sure they did not follow mom out the window? Kittens can jump and climb pretty well. This seems the likeliest answer, unless some other predator came in and took them. Perhaps they will show up in the evening outside. If they do, try to bring them back inside.

Can you get the mom cat spayed so that she does not continue to reproduce?

 

[td95]

Actually, one of the kittens was making some efforts to climb to the window, but the other two weren't showing any interest in doing so. They were climbing some other lower places. If that was the case, it must have happened overnight. I don't think a predator came in, it is a quite safe area, and the window is small enough for a bigger animal to come.
The cat mom will be spayed soon. I just waited for the kittens to wean completely.

 

[Sarthur2]

I hope you find the kittens! This is quite a mystery. Please keep us posted.

 

[Jcatbird]

Cats are masters at playing hide and seek. Keep feeding and I think you will begin to see signs of them. Kittens want to follow their mom but also, mom could be coming into heat again. She may have started encouraging the kittens to be on their own more. This might cause them to hide. If a male cat is beginning to pursue her, this might also cause them to hide. If you get them all inside again, can you close the window and keep them all in until the spay? I strongly hope and suspect they are very near.

 

[td95]

They are back home! I went this morning again to their place and saw all three of them. I still don't know what happened yesterday, but I will keep my eye on them.
Thank you for your help.