How to stop my outdoor cat from eating mice and birds and vomiting?

Yes, you are correct that Finnegan can get sick from rats and birds. Cats can get tapeworms and leptospirosis from eating rats, and can get salmonella from eating birds. It's not normal for a cat to vomit so frequently, so I would have him seen by a vet for a health check about that. Since he's allowed outside, it would be impossible to keep him from eating rats and birds unless you find a way to keep him confined to the yard. You can build a cat sanctuary where he can play and lounge outside, but it will keep him from hunting. Your other choice is to keep him indoors all the time. I hope this helps!

I think that if he is doing well on his current food (the Hill's or the Natural Balance) then they are fine to continue. It is unlikely changing his diet will change his habit of killing birds/rabbits/rodents. It in not likely due to hunger it is likely something he enjoys (as awful as that may sound to us!) and is a natural behavior for him. I don't normally recommend raw diets as there are risks when handling raw meat to the animal and to the owner (such as salmonella and e. coli). I think if you want him to stop killing you will have to either keep him inside, let him out in an enclosure, or you can try putting a bell on his collar in an attempt to warn off small critters (just be sure that it is a quick-release collar so he doesn't get himself hung on something and choke).

I doubt the whiskas is the issue here, it's more likely due to the pray or something else he ingested, blood in the vomit is a very serious symptom, if it happens again i would strongly recommend bringing him to a vet to get treatment.

They will always ingest small amounts of litter that you cannot control as a small portion sticks to their feet or gets trapped in the fur and they groom it off to keep clean. It should be not be a large amount or anything that can cause harm. If he is eating large amounts, then the only option is to change types of litter. this will be trial and error to see what he will still use without eating. Look for a different scent or texture or different size particle to see if that helps

If Jax goes outside, he may be hunting or even getting food from a neighbor, so he may no longer need much food from you. Yowling is a normal behavior in strong-willed cats. It is their way of telling you they want something, and some cats are very vocal about it! The vomiting could be a one-time thing, or it could be caused by hairballs, food allergy, eating too fast, GI blockage, intestinal parasites, IBD, among others. If you can stand the howling, I would recommend continuing to keep Jax inside for monitoring. If his appetite does not return, if he continues to vomit, or if he develops diarrhea, he should be evaluated by a veterinarian.

It is possible Princess ingested part of the bird which is causing GI upset, or some other illness. If she continues to act ill, keeps vomiting, or shows other signs of illness it would be best to bring her to a vet as birds can carry diseases and other parasites which may cause illness, and ingesting bones or other bird parts may cause GI upset or obstructions.

Try feeding smaller, more frequent meals. If Smokey eats fast, try a 'slow feed' bowl to address the issue. Sometimes, switching to a canned food may help. If the vomiting persists or worsens, have him examined by your veterinarian.