my two boys are about 12 weeks old now and i bought them at the same time, from the same cage and they have always appeared to get on well. today, however, they are exhibiting behaviour i have not seen before. they are making a low pitched sound and circling each other slowly. what does this mean ? have they fallen out ? will they resolve it or have they decided to dislike each other ? its really quite bizzare ! many thanks for any ideas on this subject