5 week old kittens- Constipation

I recently acquired 4 kittens (they were about 3.5 weeks old when they came to me), their mother is a feral cat.  My fur babies are now 5 weeks old, two (Piper and Charlie) are doing great (Piper is strictly bottle- her choice and the Charlie is bottle and canned kitten food).  The other two (Carmen and Jack) are having constipation issues (they are pooing about every other day using the triangle method which they hate!).  I am feeding them about every 5-6 hours during the day and 8 hours at night.  Two days ago Carmen began to refuse her bottle (I was giving them hartz kitten formula but discovered last night it is bad for them, I have switched them to a premixed wiskas formula), she is eating canned kitten food with no issues.  This evening at her dinner time feeding Carmen was being really fussy (not uncommon for any of them), but she was still fussing after she ate.  She became quiet and had a poo on my floor (it was normal color and consistency with a small amount of loose poo)  she seemed to calm down a bit after that like it was giving her trouble to get the poo out and she was relieved once she did it.  About 5 minutes later she threw up (there was not bile or anything but food in the vomit).  Should I be concerned for her? 

Also as I said Carmen and jack have been having some constipation issues, I have been reading these forums and was suggested to put a few drops of olive oil in their bottles (which I did last night). Voila Carmen pooped!  Jack however has not, and his belly has been swollen like he has just eaten (it goes down slightly in between feeding but is still swollen.  I can get them to poo about every other day using the triangle method (which they absolutely hate!).  Is there anything I can do to help them that I haven't?

**None of them have been dewormed I was waiting for the 6 week mark**

Thank you for your help and advise!

~Katherine 

The oil is good.  For some reason the powder forms of KMR are better than the pre-mixed.   You can also try mixing a little Canned pumpkin in the food, not the pumpkin pie filling.

Switching the formula quickly could have caused some stomach issues.

There is something @StefanZ recommends for gas.

Handsome Kitty said:

 
The oil is good.  For some reason the powder forms of KMR are better than the pre-mixed.   You can also try mixing a little Canned pumpkin in the food, not the pumpkin pie filling.

Switching the formula quickly could have caused some stomach issues.

There is something @StefanZ recommends for gas.

Click to expand...

You probably mean the simeticon (may have different brand-names, in part depending on country, the Wikipedia-article gives different brandnames in every country).  Its made for colic in infants, but several of us advisors looked at this, and we together decided it should be usable and harmless for kittens too.  You dont need prescription for it, and your local pharmacia should have it

Two-three drops in the bottle, or such a dose..

You can safely deworm with a Pyrantel poamoate preparate.  For example Nemex2 in USA, Banminth in Sweden...   There are surely other brands too similiar.   Its prescriptions free, and can be used for rather small kittens too.  Its against just roundworms, but its the sort common in kittens.

@Katherine1990

The Wiskas cat milk is not formula. It's treat milk. You should really pick up a can of the powdered KMR by PetAg. It's available at pet stores and Walmart.

You can also mix the oil into the wet food for the ones who are on solids. Usually kittens do not have constipation when eating wet food. As far as the one who vomited, it could be she ate too fast.

Which canned food are you feeding?

You can try an infant glycerin suppository for constipation as well. Just shave off a tiny piece and insert it. A tummy rub can also help.

Hopefully their issues will resolve quickly.