I’ve had chickens 3 years. Since our flock has dropped by half (thanks to someone’s dog busting into our ‘free range’ fenced in area and killing 5 of our girls… we have added to our flock. They are now 3 weeks old. 1 is now showing signs of possible rickets. Her legs and feet are weak and wobbly. Her legs also seem to hyperextend when up and running around. She lays down often. I just noticed it about 3 days ago, too late that day to get anything from store for treatment, picked up rooster booster yesterday and am wheeling their brooder out for sunshine during the day now that schools are closed (I work for a school). She was worse last night than the night before when I first noticed. What else can/should I do? She is a lakenvelder, which I hadn’t heard of until I got her.