These were hatched the last week of January. The 2 biggest chickens in the group of 40. Yesterday, I noticed one hen was having trouble walking, one foot was buckled under. Today, her sister is having the same issue. I have separated them from the flock.(1 yesterday and 1 today) I called the hatchery today, they have no information. They said they have never heard of a leg problem in sexlinks. I gave the first one rooster booster yesterday for the vitamin b, in case that is the problem. The 2 are together today, so other one is also drinking it. My question is, how long does it take to rule out a vitamin deficiency? I think it is strange the only 2 having issues are the same breed. They have all been together since hatching. I have never seen this before. Any suggestions would be great.