To spay or not

Long story, hopefully short. We had 7 feral/stray cats on our back deck. We managed to catch the females and had them spayed. Presently, in our home, we have 2 dogs, 11 parrots and 3 cats. We found one cat at the side of the road, she was approx a month old. Almost lost her, she only has1 kidney, had 1 ovary and is spayed. We have 2 other cats...offspring of the cats on our back deck before we could catch them. They are female and it appears, constantly in heat. We have not spayed due to not wanting them to undergo unnecessary surgery, although, if they get out, we are prepared to spay them. The question I have, is it better to spay them for health purposes? The three cats live together in the"cat zone" of our home, but I am concerned about having 1 cat spayed and 2 not and the long term effects of not spaying. Thanks.

Spaying is MUCH healthier for many reasons. Being in constant heat is not healthy.

There is the very real chance that one or both of them will get out when in heat.  When a cat is looking for love, not much is going to stop her and her behavior can get irritating, to say the least.

Health wise, spayed cats have less of a chance of getting cancer, as well.  There are a lot more reasons to spay than not to ...

It's not healthy for cats to be in heat all the time. There's a reason cat shows have a class for altered cats---otherwise females would only be shown when young. Even breeders spay their cats as soon as their breeding careers have ended. Besides the stress of constant heat cycles (and stress causes problems in itself), pyometra and mammary gland cancer are common in unspayed cats.

I totally understand not wanting to put them through unnecessary surgery but spaying is completely necessary in cats, IMO.