My intact male cats are fighting. Should I worry about injuries?

Poor guy. You need to get him to a vet right away to have these areas flushed and then get him on a short course of antibiotics to prevent infection. Animal bites are notorious for getting infected because loads of bacteria live on pets teeth, which then migrates underneath the skin during the bite. Neutering your pet during this healing process is not an ideal time to do this; although, if your vet doesn't mind doing a quick snip at the same time to save from having to do two procedures, then go for it. I have seen several vets who will do this to help the owner out with expenses, plus a cat neuter takes literally 5-10 minutes to do. A neutered pet is less likely to get into so many fights outside, so there is an advantage to doing this right away.

I would recommend getting them neutered as soon as possible. As they have gotten older they are becoming more aggressive and controlling of there territory. I would recommend neuter, increase number litter boxes, increase food and water dishes to start. Hopefully once all the added hormones are gone they will settle down

It's so great that you are looking after these cats. A better option for Spinx might be an injection called Convenia which last 19-14 days so they don't have to keep getting oral medications. It also tends to be very effective against abscesses. It does have to be given by a veterinarian but at that time you could discuss having him neutered to potentially decrease the fighting. Also with how this one looks it may need to be cleaned out by veterinarian order to heal. Because he may not be easy to handle sedation maybe effective for him at the time of that appointment. Alternatively there are some that in areas that you have calls which you can look into.

If the male and the female were fighting with each other, especially if he was trying to have sex with her (she won't want that because she's spayed and has no desire for it), it is possible that he could have bitten her in the forehead. I would separate them for now, and if your older male isn't neutered, I would have him neutered to stop this behavior. As for Fred jr, keep her in her own room with her own litter box, food, and water so her wounds can heal. Gently clean them with warm water and antiseptic soap. Do not put any topical antibiotic ointment on them. Although quite safe on superficial wounds, cats groom and ingest most of the topical ointment you apply and therefore should be used only under direct veterinary supervision and if there are no other appropriate options. Many human ointments contain multiple other ingredients which are not necessarily safe to be swallowed. Keep an eye on the wounds, and if they become red, swollen, warm to the touch, or there's pus, the wounds are infected. I would then have her seen by a vet as she will need antibiotics to treat the infection. I would keep her in the room by herself until her wounds are completely healed.

Yes you can take them into the vet to have them neutered if they don’t have owners. That would be lovely of you! It will cut down on fighting, but keeping them indoors all the time. will prevent any fighting. Best of luck.

They may always be enemies but there are a few things you can try to help calm them. I would start by putting some feliway diffusers throughout the house. They have a multicat version now. Feliway is a feline pheromone which is helpful to calm cats. It doesn't work on all. You could also consider putting some essential oils throughout the house. Be sure to get ones that are safe for cats. Visit oilyvet.com for more information. Also, make sure you have at least 3 litterboxes throughout the house, if possible, to prevent competition. If all this fails, you could talk to your vet about putting one (the instigator) or both on an antianxiety medicine to help calm them. I hope this helps!

How lovely of you to bring him Cactus! Even though he's not showing behavioral signs now, it doesn't mean that he won't start spraying to mark his territory and want to go outside to roam. Also intact male cats tend to be poor groomers, causing them to become matted and scruffy-looking. On the other hand, neutered male cats tend to pay more attention to themselves and keep themselves clean. I think having him neutered would be a good idea. Best of luck.