Brahma behavior

[ArcheryLady]

I have an almost 3 month old Brahma, who lays down a lot. She walks around for a short time and then will lay down and then get back up and get some food and lay down. She looks very healthy. We give them all kinds of nutritious treats, along with their food and she drinks good. I’ve checked her for mites and don’t see anything. is it like growing pains? I have two other Brahmas that aren’t quite as big as her and they do not act like that.