First of all, thank you for rescuing these kitties!!!!!!
Secondly - change your thinking. There is no such thing as "rapidly" socializing a feral. At 3 months, they're still kittens, but they were with mom long enough to learn everything they need to know as cats - and that is to not trust humans, because they don't trust anything, and they've been taught to survive.
Because they're kittens, they'll likely learn pretty quickly that humans are OK. But don't count on it. The most important thing when it comes to socializing ferals is patience
. They do not operate on a schedule, and any sense of nervousness on your part will delay the process. Just having a sense of urgency will likely cause you to do things that could slow that process down. Forget the clock and the calendar, and things will go ever so much better!
A radio is good - but tune it to a classical station. It helps calm them. Or, put a small CD player in there with classical CDs. Harp music is best if you can find it.
Purchase from a pharmacy or something one of those old-fashioned tick-tock alarm clocks. Wrap it in a blanket and put that in their bed (which should be in a box with several holes cut in it so they have several avenues of ingress and egress). This will simulate mum, which will help them feel more secure.
Get a schedule going. Go in there at the same time every day to make sure they're food dish is full, or to give them a meal of wet food. Go in there at the same time every day to scoop litter. Go in there at the same time every day to give them fresh water. Go in there at the same time every day to just sit and read to them. Cats are creatures of habit and they LOVE routine. This alone will help them come to trust you.
Just ignore them every time you go in there. The more you ignore them, the less of a threat you will seem to them. Don't look them in the eyes - this is experienced as an act of aggression. Look over the tops of their heads (though at first it's best just to not look at them at all). Once they're used to you, they'll get curious. They'll peer out from their box. Let them look. After a couple days of this, turn to look at them - but look over them, or at their foreheads. Shut your eyes for 10 - 15 seconds. Open them up to make sure they're still there - and "look" at them again with your eyes closed. This really helps build up the trust factor - it communicates that you are not a threat.
If they approach you, do not get excited. Just keep reading or do whatever you were doing. Sitting on the floor - at their level, is actually the best thing. You're far less threatening that way. Put one hand down on the floor - palm down. If they come up to investigate, just leave it there. But the palm down, with cats, is very important.
They need to understand that they can approach you and you will do nothing. THEN when they get comfortable, you can try reaching your hand out (palm down) - they've learned that that hand won't hurt them.
Remember - they don't know what the love of a human is. They don't know what petting is. They don't know they want it. All they see is some big scary thing reaching out at them.
There's a great thread "stickied" up at the top of this forum. It's called "Socializing a Feral: The Story of Lucky." This is a fabulous thread to learn how to socialize ferals. Don't get discouraged given the months it took Lucky to get comfortable. These kitties are much younger, and they also have each other.
But if you're worried about getting them adopted out, put up your ads or posters or whatever you're going to do - and when someone calls, make sure you explain that they're rescued kitties, and they are scared and timid, but that with patience they'll become wonderful pets. Even if you socialize them, they'll still be terrified to go to a new home with new people, and the exact same guidelines will apply. As a matter of fact, this is good advice for bringing ANY cat to a new home! Cats are territory-oriented, so just moving out of the bathroom will be traumatic (though kittens are more adaptable than older cats).
And PLEASE use an adoption agreement! It will help ensure that whoever is adopting one of your kitties is serious about wanting to CARE for that cat. Even charging a little bit is best, especially if you take them to a vet to be spayed or neutered, which should be done as soon as the first tooth falls out (although they can be spayed and neutered now if your vet will do it. Some vets aren't aware of the research on it, and cats can be spayed or neutered as early as seven weeks old and it is the same as waiting until the usual 4 to 6 months that most vets recommend).
Have they been to a vet yet? If not, they need to go to be dewormed at the very least. Over-the-counter deworming meds do NOT work. They do not kill the parasites, merely cause the cats to expel them from their systems - live. Which means the likelihood of re-infestation is very high.
But the most important thing is do not push them to be friendly. Let them come to you - let them do it in their own way in their own time. This is actually the quickest way to socialize them!
The most important thing to establish is that you are not a threat. Once you've gotten there, the rest will come - they'll let you know what they're boundaries are.
...and don't forget to post again if you have any questions!
Cats, unlike dogs, are not pre-programmed to want to be with us or to love us. They have to learn that they can trust us, and that's what the process is all about.
And the better your ability to ignore them altogether - as opposed to trying to engage them in play, etc. - the quicker they'll come to trust you.
Leave some toys in there for them. They'll play with them when you're not there. Do NOT leave ANYTHING with string on it out - no wand-type toys. Ferals LOVE string, and they'll chew it off and swallow it, and this could cause serious damage that needs surgery to correct for them to survive.
Little mice - even better, little furry mice with something inside that makes them "rattle" a little bit - balls - small things they can pick up and toss around, or bat around with their feet to make them move. The cardboard from an empty roll of toilet paper is a great toy. A paper bag - so fun to hide in - and then so fun for one of the other kitties to leap on!
They'll play with the things when you're not there - and when they get used to you being there, they may come out to play while you're there.