Surrogate cat mom not taking to kittens

Question
I have a nursing mother with 5 week old kittens helping nurse 2 abandoned 1 week old kittens (all rescues).  The nursing mother is not very interested in the 2 young ones and will feed them only with a lot of prompting and will not take care of them.  Do you have any advice on how to get the surrogate mother to take a more active interest in these 2 kittens?  I am not sure how common it is for surrogate mothers to accept other kittens.  We have the mother eating a/d to try and make sure she has adequate nutrition.

Answer
Hi Mindy, Thank you for the question. It is very common for mom's to take over the care of orphan kittens so I am sure this will be successful for you... eventually.
First let's go over the steps needed to do this successfully. You may already have done some of these steps but it is good information for other readers!
1. Put the orphan kittens in with the natural litter when the mom is not around. Put mom in another room so she does not know what you are doing. Do not change her bedding or make any other changes at this time. Just add the new kittens. Rub the new kittens against the natural kittens especially their faces and their rear when smells can spread from one to another more easily.
2. Make sure that nothing obvious is being passed from the orphan kittens to the natural kittens such as sneezing, eye infections, and fleas.
3. Make sure the orphan kittens are warm to the touch. Quite warm. This can be done by using a heating pad, feeding them a warm formula before introducing them to the nest, or walking around with them tucked in your chest to warm them up.
4. Now you can introduce the mom. Usually she will sniff the newcomers but then settle right down with the litter as if there was no change at all when she was out of the room.
5. When there is a significant difference in age you will have to help for a while to make sure that the smallest kittens are doing ok. You can do this by supplementing them with formula and letting "mom" do the cleaning and other chores. OR, you can remove the older kittens at intervals so that the younger kittens have a chance to get a nipple and get a good meal. In your case I would recommend supplementing the kittens with formula. This way they will not have to fend off the older bigger kittens to get a meal, yet they will still have all the other benefits of a surrogate mom such as stimulation, littermates, cleaning and training. You will also notice them suckling off the surrogate mom even if they are not getting the bulk of their nutritional needs from her. Having suckling time is very important for kittens and it is almost impossible to replicate this when you are bottle feeding or tube feeding them.

Good luck with the little ones and please feel free to write back if you have more questions.
Teresa