Sudden Behavior change in 2 cats

Hi

I have 2 cats approximately 1 year old both female and sterelised about 6 months ago. 

They are both rescues from a feral cat colony and we got them around 5 weeks old. They have always been slightly weary of people but bonded very closely with our other cats. 

After we had them sterelised they both became much more affectionate, sleeping on people and running for loves when called. about 2 weeks ago they managed to get into a gap between the apartment buildings and started hiding there, only coming in for food, We waited for them to come out one night and closed the hole they were getting through.

Neither of them will allow anyone near them, the one hides until it is dark and only comes in for food. The other meows almost constantly, If we call her she comes inside but wont allow us to touch her or go near her and she calls the entire time. 

I'm not sure what to do.

Hi Ashmac, Kinda sounds like something spooked them really badly. First check if there maybe a problem with the sterilization having become infected or anything. Medical is always the first suspect when behaviour suddenly changes. I hate to say this but number two is abuse. Does anyone have acces to these babies and could have hurt them or scared them? With all of this ruled out, it's anybody's guess. 

I would do a re-introduction to your home. Keep them in a safe, quiet room with everything they need, make sure to spend as much time in there with them as you can. Try if they will play with you with a toy. Just re-built the cat-human trust slowly and go from there. Make a good and comfortable hide away in the room that they can always retreat to and let them come out at their own pace. You could also try a Feliway diffuser in that room.

Keep us posted!

They won't let us near them, they only come into the house when we are asleep or not there, so we are struggling to get them in to try socialise them again. We have 3 other cats who all seem fine, and there has been no signs of infection from the sterelisation. 

They have never really engaged with us when it comes to playing with toys, they do play with our other cats though. 

We live in an apartment block and there are other cats around, none of our cats like strangers so they run away when other people come near them. I don't think they would have been abused by anyone as they run away from strangers.

I guess step 1 would be to gdt them to come with food and then keep them in that room and start the re-socializing process. Do you guys have time to be with them a lot?

We Work During the day but are home late afternoon, and we are generally home on weekends. We tried to get them to come for food, everything from tuna to wet sachets of cat food, tried catnip which they used to love, so long as anyone is within eyesight they wont come. I dont want to have to trap them because I think that would just add on more stress. They come in at night when we go to bed but as soon as one of us gets to the door they run out again

It looks like your only option for the moment is to let them be. As they were happy around humans before, they may come around eventually and decide it's safe again in tne house. Maybe plug in some Feliway diffusors?