They ate and grew like there was no tomorrow, until they started to suffer from sour crop, which is a fungal infection. On the advice of some amazingly knowlegable people on this website's forum, http://www.thepoultrykeeper.co.uk/, I gave them live yoghurt. This did seem to help but they only really started to get better when i moved them into the garden shed.
Luckily they no longer needed the heat lamp by now, and went out in the rabbit run in the sun during the day and snuggled up in the shed at night.
During this time my wonderful husband was busy building his first chicken coop. He did a could job and built a house on stilts with a run underneath and extending out into the garden. As soon as it was ready, out they went.
It needed a bit of updating at one point when Harley found a design flaw and decided he had to demonstrate it. I found him in the run with the chicks!! I had to rip half the mesh off (along with a finger nail) to rescue my poor birds. Luckily he didn't do too much damage and with a bit of nursing and some Savlon spray, the girls have recovered well. Once repaired and cat proofed the chickens returned to their home.
They are about three months old now, and we think we have two boys and two girls. My daughters are against eating the boys, which was the original plan, so they may have to disappear during school hours, as there is no way we can keep them. The girls should come into lay over the next month. They are at a very funny stage at the moment, experimenting with adult chicken noises! Up until now they have still been making chick peeping noises which doesn't suit their size, but the interesting attempts at proper chicken noises do certainly still need some work. They are fascinating to watch, especially when they are chasing flies, as quite often you can't see them yourself and all you see is a demented chicken running around the run. It's a bit like having a fish tank and I like to sit and watch them on a sunny day.