I just took in a mum & son from a rescue centre (8 and 18 months old). They are really sweet gentle cats but they have been strays all their lives and so are used to roaming free. The 8 month old managed to dart out this morning when I opened the door. Luckily he comes when called so I managed to get him back inside but since then he has spent his whole time at the window trying to get out. How long should I keep them in for? I live in a house surrounded by fields & the nearest road is a 15 minutes walk away. I will definitely keep them in at night at 1st but when can I let them out in the day?