I need help getting my cats to change foods

I have 2 cats, 12 years old. For the past several years they have been eating purina DM (dry) because their older brother had diabetes. We recently had to put him down and I've been trying to change foods. The first food we tried was Nutro-Max, but one of the girls started pulling her hair out in clumps. The vet said it could be either the environment change since one cat was no longer there, or it could be a reaction to the food. She suggested trying a food for sensative skin and I bought a bag of Science Diet. They liked it as well. Now I want to get them eating something good and purchased a bag of Innova for older cats. They refuse to eat it. They'll sniff it and then walk away. Neither is crazy about wet food but are surviving by eating a few bites now and then. It's been over a week and I'm getting worried. I don't know whether to try something different and hope they like it (what?) or go back to the science diet which they ate.

Any ideas??

Thanks

you may need to try a simplier food .. IMHO SD sensitive is not read the ingrediants... I suggest avoiding wheat ( the likely issue in max ) ... try switching over about 3 weeks

I agree to go very slowly....you might have to start with less than 1/4 of their dry portion the "new" food.