My kitties look like they are homeless!

I have 2 cats that have similar symptoms. Bobba is 1 1/2 years old outdoor/indor cat  and Nala is 16 years old exclusively indor cat. During the past few months they have drastically lost weight and have excesive hair loss. Their appetites have remained the same, sometiemes Nala wants more food, but I figure she is just spoiled. They sleep most of the day. I don't know what I should do. I do have 3 other outdoor/indor cats that are fine. Is it possible they have worms or some other parasite? If so how would Nala have gotten it since they don't interact at all. Any suggestions? Please help. I'm very worried, but I haven't had the means to take them to the Vet. Thanks for reading.

[PrettyKitty1]

Taking at least one of them to the vet would be your best bet. It could be seasonal. I mean, after all, dogs go through stages too. I know my dogs used to get ugly or beautiful depending on the season.

Look for weird, odd signs like, lack of appetite, too much/or not so much sleep, and a change in their overall demeanor. You know your cats better than anyone, so you should be able to tell if they're sick or not. For parasites, it may seem disgusting but you could check the stool see there are any worms there. If they are infested with worms, these will usually come out of their butt all by themselves. I've seen it!

My cats gain and lose weight. Have you seen a Cosine or a Sine wave? They go up and down, up...and down, usually it is plus or minus 3 pounds.

Have they lost a significant amount of weight? How much would you say? If they have, then the vet is your best option. Have you tried feeding them more? It may be the food. What are you feeding them? Diet requirements for senior cats are different from young ones, and perhaps there is something missing in their diet.