While we don't recommend separating the mom from the kittens until 8-9 weeks of age, they can be weaned at 4-5 weeks and should be offered dry food at all times. You can wean them onto food with Esbilac kitten milk replacer + canned food (like A/D from your vet). This will entice them to eat a "gruel." The mom definitely needs to be seen by a vet ASAP!
Hi,
She may well be ill. She could have a uterine infection or mastitis, a breast infection. She may have a fever, and not want to eat because of it. Please see a veterinarian as soon as possible. Plant o wean the kittens soon, if she is not making milk. Be sure the kittens are actually getting food as they may nurse on dry breasts and fool you, while starving at the same time. If able weight them daily to note increases desired.
Sincerely,
Dr G